The part number gives you a clue to what game it is. Gottlieb assigned part numbers in chronological order and the parts catalogs list the parts in chronological order in the back. A-12176 first appeared in the 1970 parts catalog which implies that the plastic was used in a game in '69 or '70. I pulled up photos of Skipper and others but clearly I don't have the attention to detail that Runbikeskilee does. Nice find.