Hello Panerai: Panerai A Series

Agree that OP6502 should not come up thick crown pin. Anyway, it may be good to understand the Panerai numbering system to know more about the OP-case number.
Just read some sharing from the Panerai expert. Let me share some more info about A-series watches here.

The OP-case number for A-series are:
OP6502   (PAM 1,2,3,4,9,10)
OP6504   (PAM 22,26)
OP6508   (PAM 27,28)
OP6506   (PAM 24,25)
......

The total number of units, ie. the number after the slash "/XXXX" is the total output of the same OP-case number, but separate for Luminor Marinas and Luminor Bases. Thus, total number of units for Luminor Base (2,9,10) = 1,000, while total no. of units for Luminor Marina (1,3,4) = 1,500.

1500 units for Luminor Marina (PAM 1,3,4)
1000 units for Luminor Base (PAM 2,9,10)
1500 units for GMT (PAM 23,29)
165 units for Destro (PAM 22,26)
500 units for Power Reserve (PAM 27,28)
60 units for Radiomir 21 (PAM 21)
21 units for Luminor Diam. (PAM 30,33)
45 units for Luminor WWF (PAM 37)
1500 units for Submersible (PAM 24,25)

Total: 6291 A-series watches

Additional information about B-series

In the halfway of launching B-series (around year-end 1999), Richemont decides to give dedicated OP-case numbers for the different cases and models. The timing is very close to the change from Tritium (T SWISS T on the dials) to Luminova (L SWISS L on the dials).

OP6502 split up into:
OP6518 (Luminor Marina SS PAM 1,3)
OP6519 (Luminor Marina PVD PAM 4)
OP6520 (Luminor Base SS PAM 2,10)
OP6521 (Luminor Base PVD PAM 9)

OP6504 split up into:
OP6522 (Destro Marina SS PAM 22)
OP6523 (Destro Marina PVD PAM 26)

OP6508 split up into:
OP6525 (PR SS PAM 27)
OP6526 (PR PVD PAM 28)

OP6506 split up into:
OP6527 (Sub SS PAM 24)
OP6528 (Sub Ti PAM 25)

Again, the total number of units, ie. the number after the slash "/XXXX" is the total output for both case finishes, but remained separate for Luminor Marinas and Luminor Bases (just like the case when they used OP6502).

PAM000 - Logo Luminor 44mm