Looking to buy a 1976 300d
 

I'm looking at this car tomorrow and i was wondering if y'all had any input on what to look for. I know the usual rust, but is there anything in perticular for this year model that I should be looking for? Is that rust on the A pillar drivers side a common problem? How hard would it be to find matching seats to replace the old ones?
1976 Mercedes 300D

thanks in advance.