You can make your own with a graphics program. Start by finding a good Fender logo on the web in the style you like. Copy it into your graphics program. You can clean it up there if you need to. Find a font close to the JAG-STANG part, and use the graphics program to position each letter. Print it on decal paper from a hobby shop. I spray a coat of urethane over the decal to waterproof it.
Here are some Mustang labels I made for a replacement neck. I made two in case I screwed up the first one. I also cut the paper to the size I needed, so that the unused paper wouldn't pick up any crud running it through my printer.