M21 Trans and Distributor

[enio45]

I have a late build 69 Z - 4th week oct 69. Window sticker and protecto plate call for an M21 Trans. The trans has the correct vin and production date stamped into it. The main case casting has a 661 casting. According to a number of experts, this is not correct. It should be a 660 casting. Does anyone have info that would indicate that this may be correct???.........or i have a 661 trans restamped with my vin and production number?

Also, the distributor is a 1112003 vs the 1111480 as most books call for.

Has anyone else uncovered this on late build cars?

Thanks for any advise....Ed