18-18.5 Inch Barrel Needed for 12 Ga. Super Magnum

[davisdm2008aolcom]

I have a synthetic 870 12 Ga. Super Magnum, set up for 2 3/4", 3" and 3.5" shells. I'm looking to purchase an 18-18.5" barrel and recognize that those barrels are only to be used with 2 3/4" or 3" shells. My question is, will those barrels fit my receiver, given that it is also set up for 3.5" shells? I can't seem to get any solid answers on my question. My goal is to utilize this 12 ga. for home defense and don't care about the sights but would prefer interchangeable chokes so I can dial it in. Thank You for your time!