Changing couplers on Bachman Super Domes

[DrummingTrainfan]

My long awaited Bachman Full dome in Amtrak ph. 3 liverly has finally arrived, but as got ready to attempt a change of couplers from hook-horns to some knuckles I noticed that it has some weird coupler pocket. When I was re-doing my old Bachman F40 into the cabbage I just lumped off the pocket and put in a KD, do I have to do that here too? or is there a trick to replacing these odd pockets?

[TomDiehl]

If the provided coupler pocket is too strange that it can't take a Kadee #5 type coupler, the pocket goes and I put in a standard Kadee pocket.