Papa G,I do believe the skeet and trap Model12's all had the ventilated rib on the barrel. Granted the poly choke does detract from the value, however if it is a shotgun you plan to hunt with, it is a bargain at $300.00 as was already mentioned due to it's prime condition.
About 15 years ago I bought a Model 12 from a fellow worker that was really a basket case, although it did have a 30" full choked barrel. It had a hardened untrimmed recoil pad on it, covered in surface rust, and the slide action was very difficult to operate, and the stock had some pretty nasty dings, I offered him $150.00 and ended up taking it home with me. (At the time Big 5 had a sale on pump shotguns for $149.00) Anyway when I got the gun home I completely broke the gun down, and found all kinds of birds feathers jamming up the slide rail.
To make a long story short, I placed a new Pacmyer pad all trimmed up, refinished the stock, removed all the surface rust from the barrel and receiver, and then took it to my local trap range, to which I shot a 22/25, low and behold, I was offered $600.00, for that gun, Note when it had been blued back in 1931 the steel must have had some type of mineral in it as the receiver and parts of the barrel had a purple haze to it, and no I didn't see a need to have it re-blued. BTW I still have the gun although the guy that made the offer has several times since offered to buy it from me.