All 870 12ga. barrels are interchangeable regardless of the chamber length with the exception of the Special Field version.
If you have a 1992 or newer Wingmaster with a "Light Contour" barrel, then there is a possibility that the forearm channel may need to be opened up due to the larger diameter of the standard contour barrels (Slug, Turkey, all versions of the Express model, 1985-on Wingmaster standard contour RemChoke)
This is obvious but needs to be stated for certain individuals: Putting a 3.5" chambered barrel on a 2 3/4" or 3" receiver will not allow you to shoot a 3.5" shotshell (well it will but you need to remove the barrel after firing to extract the fired hull) and under NO circumstance should you shoot a 3.5" shotshell thru a 2 3/4" or 3" barrel even if it is installed on a Super Magnum receiver!!!