Water collects in boxes under front seats and rots, could be why there's wood supports in back.
The boat and wood is 44 years old and is most likely bad .. maybe ..
Best way is to drill small holes near bottom of transom and under motor and speedo tube mounts, then check if wood shavings are wet or soft.
Most seller's aren't going to let you do something like that though ..
You could poke around with a sharp object on inside of transom and also grab motor and try to rip it off to see if there's any flex of the transom.
If you can do the work yourself it would be about $500 to $1000 in materials .. give or take a few $.
Look like it's a nice boat from pictures .. even if flake is a little dull, it can be wet sanded and compounded to it's original shine and you don't see many boats with there original vinyl.
If you took it to a boat repair shop, might $3000 or more to repair depending on stringer, floor and transom condition.
Search our forum and here .. for CVX16 rebuild threads ..
http://www.classicglastron.com/phpbb/viewforum.php?f=34&sid=ef43009ddb1a1bc1c6c55435d57bc793