Trim Codes crossover years?

My trim code tag on driver side door post shows ZJ1 - model, Trim - I52, and 10L as Paint. I was looking at an option list for 77 interior trim codes, and did not find I52 listed. My VIN shows car is 77 model (6th digit is 7), but I saw somewhere online that only early year 77's had the alarm key in the fender (mine does). I did see the I52 code listed for 76 models (Smoke Grey). Is it possible that my 77 was made using 76 trim color? Or, anyone know how to better find out decoding of options?

According to the Corvette Black Book, 152 WAS a trim color for 77. Smoke grey leather. Also from the book, starting with VIN 1Z37X7S427373 the alarm switch was moved from the driver side fender to the driver side door lock. Yours must be earlier than #27373. Mike