I have 5 Centurions right now, at least 3 of which I'll be selling. One is an early to mid 70s coffee color Super Le Mans SN Z672083. I'm not familiar with this SN format. The decals on the bike look like 1975 and prior but I'm guessing the SN indicates a later production date. Does anyone have any insight into the year made? I'll post a photo when I have 10 posts.