Henry,
Just a few off the top of my head observations:
It's certainly a real one & the serial should start with an 'F'.
The butt socket has been incorrectly restamped at some point.
The L-whatever it was & the other garbage stamped into the receiver either side of the 'T' is all spurious.
Has the barrel been shortened a little, or has the foresight block been moved forwards?
The holes in the receiver from the commercial scope mounts can be blanked off with grub screws & then covered over with weld (if done carefully), great care being taken to ensure the screw that is puddled over in the receiver ring is seated shallow enough NOT to interrupt the barrel threads (or you will never get the barrel out!).
The spurious receiver side wall markings could also be puddled with weld if done carefully, & then all made off. The weld will lead to variations in colour if you intend to blue, but if you phosphate & suncorite it (or use a similar paint to suncorite) it won't matter at all.
It is just the kind of restoration project I like. There is a lot to do but it is do-able if you have the time & patience. I am shortly picking up a L42A1 that has had similar treatment & I'm really looking forward to getting to grips with it.
ATB