Originally Posted by jonmanjiro
I've read information in Japanese that says this batch of "reissue" SPs (s/n 623xxxx) was made in 1962.
Titanium shutters were introduced from 6214xxx in conjunction with the release of the Nikon F.
The aprox 2450 nikon sp starting at 623xxxx were two batches .
First batch of 1456 was completed in may 1962 ,
This camera is probably in this batch of numbers
Second batch of 994 completed intermittently from oct 1963 - jun 1965
As demand for professionals .
Source -- Nikon rangefinder system by Robert rotoloni