SMC PENTAX 67 1: 5.6  500mm 
Produced 1989  Serial Numbers 8575xxx - 8800xxx. Product No.xxx.  Updated May 2024.

(Research Note: Since 2015 I have seen 2.06% (25 copies) of the total estimated 1,200 copies made.)

LENS PRODUCTION  (∑ lenses)  ∑n = 25 Serial Numbers observed in 10 Batches covering 492 SN min. < ∑ lenses < 1,936 SN max.
SN min. = accumulated total of serial numbers observed within 10 batches
SN max. = accumulated total of serial numbers observed between adjacent batches of other lenses.

​
8575152 to 8575160 (2/ 8)
​8576381 to 8576406 (4/ 25)
8579690 to 8579756 (3/ 66)

 Serial Numbers in 10 Batches 
(n /SN range)
8586583 to 8586863 (6/ 280)
8596660 8596663 (2/ 4)
​8600303 to 8600404 (3/ 101)

8605223 (1/ 1)
8612940 to 8612945 (2/ 5)
​8617040 (1/1)
​8800312 (1/ 1)