Something looks odd on the left side of the receiver, too.  I’d inspect more closely for a repaired hole or two

As Bert mentioned, someone has done some cleaning on the receiver a long time ago, long enough to where its got some lite rust coming back in place, either that or its old lite blue that has toned.  Doesnt look like they cleaned the lower tang, compare the blue on the lower tang and the receiver metal.   Almost looks like the receiver metal is etched in some of the photos, like with vinegar or some other lightly acidic compound.  The magazine tube and forend cap have also been cleaned.  The magazine blue should match the barrel blue, especially in the protected areas.  The wood for the most part looks ok.  If its got a good bore it would probably make a decent shooter at the right price.