model 12 trap??|Winchester Shotguns|Forum|Winchester Collector

This model 12 "trap" on gunbroker http://www.gunbroker.com/Auction/ViewItem.aspx?Item=393259488
I must say I am not really interested in purchasing this but am using this more as an example to clear something up with someone who is a whole lot more knowledgeable than I am on model 12’s.
1. He refers to this as a trap gun. Isnt this just a standard Model 12 with a full choke. Didnt all the trap models have "TRAP" or "STANDARD TRAP" stamped either next to the serial on the receiver or on the mag tube near the serial
2. Is this rib factory? The photo of the barrel address doesnt appear to have a proof mark there.
3. Whats with the 2 holes in the left side of the reciever? A peep sight on a shotgun!!!
4. 2 pluses though…It does appear to have a factory red pad and its the nickel barrel