I picked up some emery cloth on the way home and went at the barrel. Out very close to the muzzle it's stamped 11-18. The serial number puts in 1918, so I assume the manufacture date is November 1918. A very cool thing to know.
I sanded the heck out of the barrel, but some of the pitting is really deep. Is there a way to fill it? Or should I just let it go? Of course, it's not so deep now.
Right now, between the TruOil, Blueing & Rust Remover, Oxpho Blue, recoil pad and miscellaneous stuff, I've got around sixty bucks into it besides the purchase price, tax and DROS fee. That brings the total to almost precisely $300. So far, so good for a low buck, long range shooter.