Thank you, everyone, for your comments!
A few questions:
I also find it strange that a stutzen type stock was made with a takedown.
Is there a way to identify the company that did the conversion based on the type of takedown mechanism used?
Also, given that the number on the trigger guard is fairly high at 3709 and assuming that the conversion took place pre-WWII, would that point at a well known and large outfit that made a lot of custom rifles?
Is there a reference book on British gunmakers of that era that has detailed information about the trigger guard serial markings and the types of takedowns used?

Thank you!