So you did not give us a real reason for wanting the Montessa 242. Do you just want to play around with a trials bike on your property? Do you want to compete in vintage trials? Do you think it would compete in modern trials?
It would be fun to just play on.
It is a competitive vintage bike with the right equipment on it.
It is not the bike you want to be on to go up against today's bikes and courses. It was made in the "NO STOP" era and trials is much different today. Take these things into consideration