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
I have owned several 40/45 Super Sporters in both the early and late configurations and I have all of the catalogs from that period.
As per the catalogs and those that I have owned or seen, they are/were as I have described them.
Although you never say never with a Savage product, I have never personally seen an early 40/45 with a schnabelled forearm, nor have I ever seen any 40/45 with a schnabelled forearm that didn't have the later magazine release style that featured a button inletted into the right side of the stock. Could it be possible that the stock on your early 40 was reworked to have a schnabelled, rather than rounded "English style", forearm tip? Non-cataloged configurations do happen, but generally close to the transition date of a configuration change or close to the end of a run and subsequent discontinuation of a model, when some of the last guns were put together from whatever parts were left in the warehouse without consideration of the then current cataloged configurations.
The last 40/45 that I had contact with was a nearly mint 45 in 30-30. It was of the early configuration style, rounded forearm and bottom magazine release tab, and was SN 295x.