I just purchased a new Remington 870 Express Synthetic with the 18.5" cylinder bore barrel not threaded for RemChokes and +2 magazine extension. What I found strange is the receiver just says "Remington 870" and not "Express". It also has a tactical forearm that does not go over the receiver when opened and is ribbed, not checkered like the sporting model. The receiver is not drilled and tapped. The serial number starts with an RS and ends in an E and also the safety does not have a lock built into it. It looks like a cross between a synthetic sporting and tactical 870. I'm sure this is a NOOB question but is the receiver still a magnum receiver capable of firing 3" shells. The barrel is marked for both 2 3/4" and 3".