Retroactive Unprepared

Unprepared stops a dude or attached cards from using their abilities, but what about abilities that have already been used and are in effect? For example, in the first shootout play Thunderboy Nabbe uses his ability to become a three stud. The next play Unprepared is played on him. I assume the Unprepared modifiers would apply from his 3 stud, not 1 draw, correct? His ability has already been used and has now become an effect in play. Unprepared doesn’t state that it cancels effects in play, just that they can’t use their abilities and get -1 bullets.

Unprepared does not cancel abilities that have already been used.