I have a 75 mk3. I obtained a wm-2 rim from a 73 norton. The rim pattern,on the 73, appears to be 180 degrees out from the rim pattern on the 75. It appears that if the hub was flipped 180, then the rim would work. The question: is there an offset for right and left side disk brake and will I be able to use this rim. Thanks for any replies in advance.

72,73,74,75 (disc)front rims are all the same. The whole 75 "wheel" is mounted 180º from the earlier bikes... Actually the forks too. Regardless, there is a correct orientation for the rim/spokes to match/align with the hub. The offset is identical and results in the wheel being centered in the forks. If it doesn't center in a 75 then it won't center in the other years either.

Thats what I wanted to hear.I guess I just need to take a closer look at this.Thanks again for your time.