Have a 629-2 Mountain Revolver that had the single Magnaports flanking the fs ramp like the nickel 29-2 posted just above when I bought it used years ago.
Read somewhere that a batch of these were sent to Magnaport from either the factory or the distributor for the same treatment, dunno if that's true or this one was sold this way .
Will have to break it out of the safe and compare to my 629-3 Mountain gun side by side on the range one day.

On a side note the First time at the range noticed residue on the front site blade red ramp insert.
Second time the baughman ramp insert went missing.
Have since replaced the Baughman red ramp with a Patridge fs blade with gold bead insert.