You would really need to do a hard look at these cars in person, and with someone with background on the cars. Yes, they indeed made the 230 SL in 1966, but the car you have pictured is an early car as the spare tire in the trunk is in a foot well on the left hand side of the car. I do not know when the change was made, but that should be findable by the question just posed.
Answering other questions about restoration and other costs, is almost impossible to do with just photos to go by. There are too many perils and potentially hidden issues. An example would be the rust you ask about by the doors. That is quite possibly residual glue from the carpets, but to know for certain, you would need to look at the car. Lots and lots of questions here.
While $10K might seem cheap, the old dictum, there is no such thing as a cheap Pagoda rings as true as ever. There are a myriad of restoration costs.
Yes, a lot of parts can be obtained from the Classic Center, but there are also a lot of other parts supplies out there, as providers.