[My gun was the basic 2 3/4 fixed choke.]
[I purchased a 26" steel/lead, 2 3/4 or 3" barrel.]
Those two statements say it all. There's no need to "check". Sorry, but you bought the wrong barrel, period.
ANY barrel that will successfully shoot, and is marked for " 2 3/4" or 3" " is a magnum barrel, that will not work on your older, non-magnum M1100 - even though it will physically fit the action.
Deanmac
No disrespect intended, but rangr44 is dead off.
A Remington 1100 steel shot barrel, chambered for 2 3/4 and 3 inch shells works just fine in the older 1100's with 2 3/4 inch receivers. And you can fire 3 inch shells from them safely, Remington simply recommends not using 3 inch LEAD shells, as the recoil is more intense than 3 inch steel, and they claim if you do so, it will shorten the life of your gun.
The problem comes in, as you say, because the 2 3/4 inch chambered barrel has 2 gas ports, and the 3 inch chambered barrel has only one gas port. Results vary from gun to gun, but in most cases, the single gas port barrel does not cycle the very light dove loads, it does, however usually cycle the slightly heavier trap loads with 1 1/8 ounces of shot and on up.. YOu just can't have it both ways with an 1100.
I know this to be true, because I purchased a new Remington steel shot barrel last year for my 1974 vintage Remington 1100, and have used the new barrel successfully with both 2 3/4 and 3 inch steel shotshells and also spoke with Remington in depth about this before making the purchase.
However as you state, if the very light dove loads are your priority, then the reality is, it isn't the barrel for you.