I recently purchased a large lot of Vectrex prototypes and I'm trying to find out how early they are in relation to their production counterparts. I've done some digging but have only been able to find years in which games were released and not actual dates. One prototype in particular, Pole Position, is dated 8-15-83. I've seen it listed as being released in 1983, but no actual reference to the month/day in which it hit shelves.

I have about 15 or so prototypes I'm trying to get release dates for, so any and all help would be greatly appreciated.