I am 99.999% sure it is replacement wood; looks like walnut with some kind of gloss polyurethane finish. The receiver is NOT a Magnum receiver - it may have been retrofitted with a 3" ejector and spring and been refinished, because the bluing does look really good, or it may have had a 3" system to start with, because some 2-3/4" guns did go out the door that way. It is a 1984 vintage receiver, if I am reading the serial number right. The barrel is a later RemChoke barrel that has been put on the gun. If it is a Light Contour barrel, it is the first one I have ever seen that did not say Light Contour right on it. Also, before the Light Contour barrels came out, Remington had gone back to the much lighter style of rollmarking than on that barrel. Nothing wrong with that barrel, I just don't think it's an LC. Looks like a lot later than the early '86-'87 era RC barrels, because they were heavier still. In 28", it should handle fine.
Nothing wrong with it, but I think it is priced pretty high considering it is a put together gun, and I don't know if it would function with 3" shells. I'm not a lefty, but if I was and didn't have a left handed Wingmaster I would probably jump on it. It can be converted to 3" pretty easy if it isn't, but if you don't know how to do it yourself, it is pretty costly because most gunsmiths will replace the rivets and do a refinish. AND, Remington doesn't list a Magnum Left Handed Ejector as an available part, so you would still need to do some modification.