Here's a question; when was these date codes used:

P9M15 P9P15 P9R15 P9S15

August, September, October and November of 1968 or 1969, or BOTH???

Did they get used a second time when the 69 camaro was built later than the
usaul end date of July 31st, into Aug. Sept. Oct. Nov. 1969???? How to know if
a muncie was built in October 1968 or October 1969?

Issue came up in a discussion.

1968. The date codes are model year, not calendar year.

I believe his point is that they made camaros for the 1969 model year in those months in 1968 as well as 1969.
I am not sure but I would think the date code might have been the same but the vin stamp would tell the story.

Yes they did, but the whole rest of the GM world went to the 70 model year in August of 1969, so late model Camaros carry P0 coded Muncies after the P9s ran out and three letter coded rear axles, like CBU instead of just BU. Muncie didn't know where their transmissions were going so they just rolled the model year code up to 1970 after about mid August of 69.

Yes, but they would be stamped different. Most of the early 69 Muncie stamps wouldn't have the suffix, the late 69 stamps did.

The late 69 Camaros used P9xxxx coded Muncies til the end of production. The model # indicated the application so Muncie knew where they were going, but this had to be a PITA for Muncie. 2 different date codes used at the same time (Camaro and Vette vs the rest of GM).

Interestingly, late 69 Camaros with auto trans had 70 model year trans dates.