Brillliant Commander allows you to upgrade one monster in a newly revealed area to a master monster. Can you do this if you have no additional master mosters of that type?

(We are playing quest 3 of the base game and the heroes are about to enter the last area which places all three of the monsters available on board)

Sadly, my feeling is that the answr to this no but want to get opinions.

.... unless the Brilliant Commnader card is considered a 'Keyed' event per the clarification in quest 2 that says:

Note: ... As a general rule, named monsters and monsters keyed to events are always placed when they appear in a Quest, even if there are not sufficient figures to place them on the board. (page 5 of the quest booklet, and reiterated in the FAQ)