It's been around long enough to have gained cromulence, I think.

I started using "OG" ~16 years ago to disambiguate the Motorola Droid that I had (which was the first Android phone available from Verizon) from the Droid 2, 3, and 4 that came later.

"OG Motorola Droid" has specificity, while "Motorola Droid 1" is something that never existed.

Anyway, my usage is old enough to drive a car. :)