Leaking rear seal; big deal or not?

[Dave Rifkin]

I am looking at a 1969 Corvette for purchase. I have spoken to the owner (the cars located in Georgia) and he seems to be very open about the cars condition. Original 350hp small block car, recently rebuilt but he says it appears to have a minor leak coming from the rear seal. Is this a huge undertaking to repair?
I have yet to see the car in person, in fact, the seller may be having second thoughts about selling.
What are your thoughts about the seal issue? Everything else is cosmetic; the paint is starting to show it's age (15 year old paint) and the chrome is starting to lose some of it's luster. These items are not that big of a deal to me as I intend to drive and enjoy the car and hope to bring these areas back as finances permit.