Any M1 Carbine Gearheads out here?

So the barrel is marked 7-43, Inland MFG.  and I found this:

There is a "P", a "w" and and "s" stamping here. Anyone know anything about this stuff?

Trigger Group housing looks like this:

I have read two books on this rifle and book smarts don't translate into experience. What should I be looking for on this rifle to determine its provenance?

Thanks for the help on this old girl!