Still couldn't locate the Goodmark ones on ebay.
I recall a discussion several years ago here that Brian from Gbodyparts.com was saying that he had been buying these clips for years and they never came in a box. I know they came in a box because I've purchased them and they came 10 to a box. I've never seen them any other way except in a box. And for a while, they were restricted in how many you could buy at a time, for some unknown reason. I think it was limited to 2 boxes per order. Well, there was ways around that...Then that restriction was lifted.
You can always tell a non-GM one. The aftermarkets are lighter in color. And I'm betting they're not as tough (initially) of a material. The GM ones will get brittle after years and years, however.
But here's a picture of a box.