I finished work early, so had time to poke around the web. I know a lot more than I did before but maybe not nearly enough.
These decals are made by Original Wraps, a Golden, Colorado sign company bought by 3M back in 2011. I found two toll-free numbers, called them and left a message. About an hour later, a sales rep from 3M called me. Here's the deal:
The GM part number is: 19299185
The 3M graphics number is: GMSBEV001
These decals are still available! Unfortunately, the only configuration listed in their database is the black graphic with the cutout design and not the inverse which I received. I sent a picture of my car to the rep after she volunteered to investigate the discrepancy. I'm waiting for her reply.
Meanwhile, the procedure for buying these decals is through the dealer. They then order the decal through their API (accessory distributor installer) using the part numbers above. From what I gather, the problem some dealers have with the decal comes from the requirement by 3M that their graphics be professionally installed, otherwise there is no warranty. Dealers can sign up to be installers and get certified but why bother if there is little demand. (speculation on my part) BTW, the 3M rep said these decals were so small they didn't require professional installation.
Anyway, if you want one of these decals, I would call the dealership where you got the car and find out if the parts desk will order it for you. If not, post to this message and if there is enough demand, maybe we can convince 3M to sell them direct.
Did the decal come with instructions at all?
No. The only things in the box were the decals and a picture of a Spark EV sporting the decals. Nothing to say where they were made or even an invoice of their purchase. If someone actually succeeds in receiving these decals, and you want some installation help, let me know and I'll post my procedure. It's actually pretty easy.
Good Luck!