John - the shafts are unmolested by Marlin... Standard BMW parts.
Looking at your photo again, you may be able to cut the boot off at the correct place for it to be connected, and then use a stainless tie to clamp it on to the shaft.
If you cut off the portion that has the larger diameter that was incorrectly clamped to the top portion of the shaft, it should fall to the same place as where my original boots are
I can't see that your shafts are different to mine. But if all else fails, whip the ones off your other donor and have a look.