Coldwargrunt and Everyone:
Thanks for all the details and information on my model 12.

Barrel says 2 3/4 only. There's no stamping at all about 3 inch.
There is NO stamping saying "trap" or pigeon.
The raised rib has rectangular posts.
TWO pins on the rib. Duck bill rib.
Barrel says Nickel Steel

It's a beautiful shotgun and functions extremely well. Very very smooth in operation.

Sorry guys......................for the millionth time I've tried to post photos. Changed sizes, etc., in an effort to make things work. Now, the systems says "Sorry, the board attachment quote has been reached." Would love to share photos of this model 12 and get more thoughts. Hopefully the attachment quota situation will be solved sometime soon. Thanks for all of your input. I'll attempt to post the photos again in time.

Thanks,
Jon

Jon B.
I'll try to add a bit to this but most was nicely covered. The square post add-on ribs were called "Money Maker" ribs. Many shooters found these attractive in the both.. low and high version. If the shotgun left the factory that way, which I don't believe it did, it would have 2 proof marks, 1 being on the front/upper/left of the receiver with the other being on the barrel extension right in front of the one on the receiver. Many guns were sent back to the factory for such upgrades and in my old eyes, they are as valuable as some that were factory built, same parts, with exception of the Pigeon guns that were extremely smooth worked over (actions) before leaving the factory. Later in the "Y" series "72" thru "74" the 12 was produced with a rectangular post under the rib. To me.. there is not a bad one out there, they've been around shooting strong for over a 100 years now and I'll say they'll be here doing the same in another 100. Have fun with it.

Collecting the 12's since I was 18 ..,
Pops