You are correct that double wrap bands can be used in any 904.
I think the case pawl is different though and they have to be used as a pair.
(I think I remember that correctly)
You have more current experience than I do on them.
I think your right on the pawl. I forgot about that. Actually I probably don't have more current experience with 904's as everything I've done in the past few yrs. has been 727's. I just knew about the rear band differences.
Tony bought up a point about the rear band on a /6 being different. I had forgotten but I did notice they are listed seperately. Not sure what they did different as I haven't been into a /6 904.