Closest Happ stick would be comps.
I was under the impression that they were Supers also...
Not on my MVS-2-25 (for all that is worth) ... they look a lot like Comps and have the square actuator, but the bottom of the base is square not round. I actually thought about swapping the sticks out for Supers when I got the cabinet, but everything indicated that these were original sticks and they still work great.
I have seen pictures, including the original flyer for the MVS-4-25, where the sticks did look like Supers (nice chrome shafts, albeit with red tops). However, I have never seen such sticks on a live machine, either on location or at auction (and we get a lot of Neo Geos at auction here).
This is one of those "where is Paige Oliver ?" times.
Cheers.
EDIT: Having said all of this and having looked at the pics on HardMVS, I tend to think that either Comps or Supers would be suitable and I personally prefer Supers.