Would you consider this?
The objective is to not to give away information that you’re going to the range (it’s a California thing).
As far as theft is concerned, it’s no help since guitars can be easily pawned so it’s not meant to keep away thieves. I don’t leave firearms in my car.
You ever watch the movie Desperado? 
“Bring your guitars”
I have looked at multiple rifle/gun cases that are guitar shaped. I think it is a great idea. Problem is, they are stupid expensive. Converting an actual guitar case a bad move…they are likely not sturdy enough.
The original link didn’t offer much info I had to go to guitar center to get specs.
The GWE-Elec hardshell electric guitar case by Gator Cases is built to withstand the rigors of transporting your electric guitar to gigs and practice spaces. Constructed from durable plywood and covered in a protective Tolex material, the GWE-Elec case shields your guitar from bumps, scratches and weather. The plush interior padding cradles your guitar to prevent damage from impacts, while an interior accessory compartment gives you space to organize picks, cables and more. For added security, the GWE-Elec case features locking latches to keep your guitar safe when unattended.
Durable Plywood and Tolex Provide Maximum Protection
The GWE-Elec case is built from high-quality plywood, one of the most rugged and impact-resistant materials available. The plywood is covered in a water-resistant Tolex PVC material that protects against dings, dents and moisture. This durable combination can withstand the rigors of transporting your guitar to practice spaces, recording studios and performance venues. Your guitar will stay safe and protected inside this road-ready hardshell case.
Plush Padding Cushions Your Guitar
The interior of the GWE-Elec case features thick plush padding that gently cradles your guitar. Extra padding in the neck cradle supports the sensitive neck joint area. This high-density foam padding absorbs impacts and prevents your guitar from shifting around, keeping it safe during transport in vehicles and handling. Your guitar will stay cozy and protected inside this plush interior.
Interior Compartment Stores Accessories
For added convenience, the GWE-Elec case includes an interior accessory compartment. This spacious compartment gives you room to store important items like guitar picks, cables, straps, tuners and string sets. Keep all your guitar necessities in one place for easy access before and after practice or performances. The accessory compartment adds useful storage space without compromising the safety and protection of your guitar.
Locking Latches Deter Tampering
For extra security, the GWE-Elec case comes equipped with locking latches. These heavy-duty latches securely lock your guitar inside the case to prevent tampering or theft when the case is unattended. Locking latches give you peace of mind that your guitar will remain safe even when the case is out of your sight. Keep your guitar protected from prying eyes with the GWE-Elec’s locking latch system.
Put a big label on it that says ‘Job Applications’, no one will steal it. 
The easiest way to get away from rifle looking case is just to buy regular rectangle / squared rifle case and put either sticker or velcro patch with keyboard on it.
I’m a musician, whenever I drive to the range 
I use one of these; it makes it easy to carry all my ammo and firearms to the range.
The Guitar Man!!! 
That instrument in the guitar case will be playing a LITTLE TOO LOUD!!!
I don’t think anybody directly answered your question -
YES! I would definately consider this. 
Did you buy it yet?
No, and it’s now the Stupid Deal of Yesterday 
Have a couple Roadrunner cases for guitars and I think they’d be sturdy enough for an AR15. It’s a square case and with some slight modifications may work pretty well.
I lived in Ca. Most of my life and as a firearms lover I found that the perfect case for my AR15 pistol is a tennis racket case that is a perfect fit! It’s also great for my CMMG PCC!
When I go to the range, I pull my tennis racket and my range bag out of my trunk. I’ve had the blue and white racket case for years now and except for at the range, no one is the wiser.
Now that I’m retired in Utah, I don’t have to worry about Red Flag laws, magazine volume b.s. or any of Commiefornia’s un Constitutional 2nd Amendment laws.
My son packs his AR in a guitar case he bought online. It’s a hard shell case, and for the price he paid for it, it’s very sturdy. It’s a Chinese knock-off of what used to be an American made brand. He bought foam cubes to secure the firearm in place.
WhooEEE! I GUAR ON TEE that if you show up at the range with one of those, the NRO (Nazi Range Officers) are going to come down on you hard. But you’d be welcome at Taran Tactical.
