Confirmed. Just fired up the GOTM TSG 43 game with the Huns. Popped a ruin to get a battering ram and then puppeted Mombasa (cheesy, yes, but I just wanted a puppet to test this).
Rolled forward a few turns to take Legalism ==> free monument in puppeted Mombasa.
Rolled forward a few turns to take Legalism ==> free monument in puppeted Mombasa.