I have an m1 carbine that as close as I can tell is a mishmash of parts. Here is the lowdown:
Underwood receiver and barrel. Receiver is SN 2380xxx. Has a stamp .5" below the SN that looks like a 'T' with a circle going through it. I think the SN puts it in the mid 40s?
Front sight stamped on the top flat with 'SI' on the left and 'U' on the right, both between the outer guards. Then on the barrel 'UNDERWOOD' with the flaming ordinance and a 'P'.
Next, the barrel clamp accepts a bayonette and is marked j.m.c.
The upper handguard is much darker colored than the stock, and I find no identifying marks in the stock itself.
The rear sight is adjustable for Windage and elevation 1-3. It hangs over where the SN is located. It has IR CO on the right hand side.
So, my question is, is it worth trying to find all the components to set this back to original? Or should I accept it as it is and continue to use it as a shooter? I will try to post up pics next chance I get.
It sounds like a military rebuild, possibly bought through DCM. Both the adjustable rear sight and the bayonet lug are late WWII or postwar upgrades.
The serial number dates the gun to March or April 1944. The T means the receiver was made for Underwood by Intertype Corporation. "IR" is International Register Corp., which made replacement/upgrade sights. "IS" is seen on Inland carbines as well and was probably indicates one of the parts made for Inland but transferred to Underwood.
The maker of the stock is probably identified in the well, but a replacement would not have the Ordnance acceptance mark.
Now, as to "restoring" that carbine. I would leave it alone. Even if rebuilt, it is probably as issued especially if you can trace it to DCM sales. If you try to find the "correct" parts, you will be in a world of fake repro parts ("What mark do you want on it?", a parts dealer once asked me.) of poor quality that might not fit. And anyone even marginally knowledgeable will consider the gun a fake.