North,
If the car is a two hour plane ride, get as much info from the seller as possible before you decide if it's worth to look at. History of the car, receipts he has, documentation....etc. If you are going to take the trip then I would suggest you buy literature that gets you informed on what to look for. Try ncrs.org for their publications or "Corvette by the numbers" is a good book that deciphers every possible part on these cars. Obviously, for someone who is looking for originality, a matching #'s drivetrain would be a siginificant factor.
The L79 wasn't exactly rare but it's a great mouse motor that people opted to get in these mid years over the stock 327. If it's #' matching it makes the car that much more desirable from a collectors point of view, but you can have just as much fun with a NOM motor. Just pay accordingly.
Good luck with your search and try to post pics.