I have an NOS Commando crown and stem laying about(yoke or trees or whatever), it has part# 061133. It looks identical to old Atlas/Dommi parts I have except it does not have the little hole drilled and tapped in the bottom for a steering damper anchor bolt.
Same casting number as Domi but the casting appears a bit thinner and lighter in places like they cleaned up the casting pattern maybe. Spacing on it between the fork tubes and stem looks the same as an Atlas. It is painted silver.
In the parts books for Dominators and Hybrids they call it a crown and stem or a crown and column and the top "tree" is always called a Head Clip, in the late Commando parts book I have they call them upper and lower yokes. I don't have a pre-73 Commando parts book though.
I know that when the 850 came out that they tweaked the steering angle a bit and came out with a new set of "yokes", they would have to if they wanted to keep the TRAIL of the front forks ahead of the tire patch where it should be. Mixing up 850 and 750 Commando yokes can lead to too little or too much trail making things either dangerous or slow.
So the 850 vs. 750 Commando difference is where the stories about different offsets come from. I think the 1972 and earlier Commando fork yokes have the same critical dimensions as Dominators can be swapped. I think it was for 1971 that the Commando got the yokes with a cleaned up more modern look.
Before I swapped front fork parts for ones from a different year Norton I would make sure and do a lot of research to make sure I was not doing anything dangerous.
Before I bought a set of yokes from RGM I would talk to them and clear a few things up. When they call one set of yokes "featherbed offset" and another set "Commando offset", they may just be saying that one set will work with all pre-850cc Norton frames and the other set is for the later 850 framed bikes. Again making certain mistakes with this could see you in a tank slapper at high speed, or dead.
Yes the pre-64 bikes had the 7" stanchion centers. This will not take quite as wide a tire as the later 7 3/8" jobs, but for anything but top-level racing this will not matter. The 7" jobs are cleaner looking because they don't have the hole for the lock cylinder in them.
I dont' need this Commando part and will probably get rid of it soon.