M_Boats: Ida rudder

Mr. Montgomery, My Montgomery 17 was manufactured in 1978. I now have a chance to install an Ida sailor rudder on it from a 2005 Montgomery 17. That setup uses three pintles whereas my older stock rudder model uses only two. Can a third be added so this setup will work on my boat or is there some other consideration that needs tending to? You mentioned you have a stock of old parts. Do you have a set of the old grugeon/pintle (s) available? Regards, Tom B