Yeah all the cars in the D world are referred to by the last 5 or 4 of it's VIN. I almost had #6078, an 81, many years ago
I'll pick one up someday.
You saw 502? cool! I have a pic of it somewhere from the Tennessee meet I played at. Just checked an early attempt at a website of mine when I was 14 or 15- it's still up!
http://www.twinturbodeloreans.8m.com/