Factory VR 42s commence around SN 125,000 (1954). The donut post pictured was the first variation and is seen till around SN 149,000 (1957), per Schwing. This may give us a clue as to the approx time the aftermarket installation was done by Simmons on what was, I suspect, originally a prewar/transition field. Original bbl/receiver proofs are hidden beneath rib/extension.
Metal has been redone, buffing is obvious. The original rust-blued bbl finish is gone. You might think it was all done by Simmons at time of rib install/bolt jeweling/etc. But why would the offset proofs not be sharp? So I think the metal has been "addressed" a couple of times, post mfg.
Wood is not original to the gun, and not factory IMO. The pad is proud of the wood.
All the above notwithstanding, I think it is a very nice gun. I think donut post ribs are the neatest. I had a similar donut post 42 redone by Simmons with upgraded wood and a Cutts. I am very sorry I let it go.
Modified in 42s is usually very close to factory skeet in actual constriction. They are murder on clays thrown on a skeet field and a VR adds just the right amount of weight up front.
Sam