...and, yes, they are. Here is a quick shot at the story, now that I'm not thumb typing.
Bought the bike in '73 for $50. At the time it had an A50/A65 moustache top yoke, but I didn't know a damn thing about original parts. Put $3K of '70s money into having a shop restore the bike. In Novermber of '79, on my way home after a beautiful day at Malibu Beach, a kid made a left turn in front of a rather novice rider making a legal, but dumb, passage through a green light. After sitting in storage (mostly outside, the bike, not me) for 23 years, I decided to give restoration a try. Still not knowing anything about original parts, I bought A10 top and bottom yokes on eBay. I also pounded out some dents and had my headlight ears re-chromed. Lo and behold, my beautifully chromed headlight ears were not long enough when I went to reassemble the front end. After doing the research, I decided to buy a replacement A50/A65 top yoke rather than new ears and new chrome. Much cheaper, and faster to the finish. Rebuild took around three years at my slow pace. Rode her around 60 miles before lack-o-sludge-trap-knowledge gave me another opportunity to rebuild the engine.
One thing you might notice with the A50/A65 yoke is the steering lock on centerline. A10 steering locks are off center. My answer was to attach a metal plate to the landing on the steering head where the A10 locking hole is found, then, make a new hole in the new plate. Works fine, since steering locks are just mild discouragers anyway.
Richard L.