One of my venders makes custom emblems that are not decals but they are domed emblems that fit both the rear and the rack. They are available in many different colors and looks from chrome to brushed alum. to brake light red etc.
The emblems they make for the Corvette indents are licensed by GM. I have some examples on my web site
www.automotiveupgrades.com/
listed Custom Emblems.
Any questions-let me know. Ben