Same.
There are three different hubs that are almost identical, and a fourth type that is operationally identical (but looks a bit different).
1. Early. Ran from the first RT1MX to the 76 models. Can be identified by the nine small ribs between the spokes on the non-brake side. Casting number is same as RT1MX prefix (322?)
2. Common. Fitted to virtually everything 77~82ish. Basically identical to above, but doesn't have the little ribs. Has three little tabs sticking out of the non-brake side for IT speedo drive. 1K7 or 2K7 prefix cast in.
3. DT125/175 monoshock. Still basically the same thing, but has speedo drive on the brake side, and the three little tabs are missing. 2A6 prefix.
4. YZ-K (maybe J as well?). Different style ribbing around the outside of the drum, that I can't explain. Can't recall the prefix - 23X maybe?
There's also the TT/XT500 type hub that sounds just like #1, but has a much larger drum, and there's also the XT550 type which sounds like #2/3, except its got a larger brake than the YZ type hub (and smaller than the XT500).
The brake backing plates for the YZ-type hubs are a bit trickier.
1. Twin shock + first gen monoshock. The brake lug on the fork and the cable are parallel.
2. Monoshock single leader. As above, but the brake lug is at about 45* to horizontal, and the boss around the axle is a lot longer (well, wider).
3. Angled twin leader. From YZ465, YZ125L and maybe others. (The 465 has steel arms, 125L has alloy, if you want to be a real train spotter).
4. Horizontal lug twin leader. As the name suggests, the brake lug is parallel to the ground. These are the most common type - from the ITs and most YZs with the twin leader front brake.
This pic shows a bike fitted with a #2 type, and #1 type being held below it. I was attempting to hold the lower one at the angle that the lug would be in a set of non-leading axle forks - note the angle of the cable stay relative to the brake lug:
Types 2,3 & 4 can be interchanged, but it puts the brake cable at various whacky angles.
Alternatively, if you match the LHS fork leg to the brake backing plate, then you'll solve the whacky angle thing.
Hope that makes sense. I'm a bit vague on exactly which bike had which type of twin leader, but that's a good start.
Can help with a hub (not a complete wheel) and a type 4 twin leading brake, if they're any help to you.