M1917 Mystery Receiver

[HOOKED ON HISTORY]

I am wondering if the receiver is from a test bolt fixture that someone converted into a rifle.

--fjruple

Thinking out loud here. I do know some older commercial firearms had no serial numbers (mandatory post 1968?)
Perhaps this is a test fixture or other receiver that did somehow missed serialization but was bubba stamped at some point in fear of the GCA ? Hard to tell from the photo but a close look could probably determine if a SN was ground off.