This is exactly what I thought too. Just wanted make sure I was on the right page before sending these back.I have a few Browning 12 gauges. The Invectors are older and shorter. The Invector Plus are newer and longer backbored. Then there is the Invector DS which is the latest.
None of these are interchangeable. Even though the Invector Plus may screw into the Invector threads it will be sticking out too far and part of the choke will be unsupported in a way it was not designed. I would be very concerned about shooting that... but I'm no expert