Model 11 16ga serial number question

[smileypsi]

We have an Model 11 16ga and I am having some trouble getting the information on this shotgun and am looking for some help. Here is a brief rundown of what's on it.

The "Model 11" is actually stamped on the open side of the bolt, there are engravings of a duck on on side of the receiver and a pheasant on the other.
The serial number is 1556432. The problem is that doesn't seem to match with the numbers listed here. http://www.remingtonsociety.com/rsa/questions/FR07

The make even more confusing, the barrel is stamped with "IMPCYLLRR" followed by a plus sign with a circle around it. Needless to say, I'm completely confused by this...

Does anybody have some ideas or thoughts?
I appreciate the help!

[Researcher]

The old factory ledger ends during WW-II but the Model 11 and its three-shot brother The Sportsman were manufactured until 1948. The LRR on your barrel is the date code -- L for February and RR for 1946.

[smileypsi]

Thanks for the info. I appreciate the help.
Does the "IMPCYL" in front of the LRR mean anything though?
Thanks!

[Researcher]

That means the barrel is choked improved cylinder.

[smileypsi]

Thanks!
I really do appreciate all your help!