Matching #'s question

[Jim Mulvey]

I apologize in advance if some of you may think this is a dumb question. I recently purchased a mint 1969 Z/28, and I am very happy with my purchase. However, upon further examination I have reason to believe that the Muncie 22 is not original to the car. Its code is P1k28C, which if I decoded correctly is a 1971 tranny. FWIW, the seller disclosed all the #'s but I have been educating myself since I purchased the vehicle (mainly through here and other sites). So I don't feel cheated in any way. It seems that all other #'s match up and I am working on getting the car certified.

I quess I have two questions:

1) Am I right about the tranny code??

2) How much of a deduction is this when it comes to value, percentage terms would be helpful.

Thanks in advance!!