Originally Posted by BillM
On the older 2nd gen guns that would be correct---the 9mm guns had a
single pin locking block and the 40 guns had a 2 pin locking block.
Starting with the 3rd gen guns (at least 10 years ago) they all have
2 pin locking blocks.
Currently the lower frames on 9mm and 40 S&W Glocks are identical. The
only part on the lower that is different is the ejector, which is not actually
a part of the frame.
Thanks for the clarification.