If you are talking TR2/TR3/TR3A...then the only correct one is MPH below the rings. If you are talking TR4, the inside the rings is correct. The TR3B’s I’ve seen also have below, but I would not doubt there may have been some later in the “B”, since it tended to get many TR4 parts.
Then...the early under ring speedos had periods after each letter, i.e. M.P.H.
By the late TR3 the periods were gone.
Then, there are the PN under the needles. There were several of these, and the gear range is also printed on the face, which changed based on gearing.
Finally, there were “KPH” versions...presumably with the same gearing differences.
Did you see anything beyond these? I’m always interested in variations...