I have 2 m40's. one is #422x from 1929-30 in .300 sav. with snable foreend and savage "eyes" for the strap. The other is #1538x from late 1936. It is in 30-06 with a round foreend and replacement sling swivels. Neither is drilled for a scope and both have the magazine release tab on the bottom of the stock. From my research I think the bottom style magazine release is 1936 or older
