Not sure what reply you seek. It appears you are rebuilding a boat that was manufactured in the late 60’s and 45 were launched.
It is highly unlikely that you’ll find a supplier with a OEM boom on the shelf anywhere.
What to do? Get some original specs and then talk with a spar manufacturer.
A quick database search yields this info.
E is the length on the boom from the mast to the end of the main sail. You’ll need a boom at least that long. Then you’ll need to identify the hardware you want for the rigging you desire.
Ain’t refitting boats a fun project.