The cylinder leak down test does not confirm that the valve guides are the problem, but it can eliminate ring and cylinder wear as the problem, which would leave valveguides as the most likely culprit.
I'm sure that some of the valve guides/seals in these cars (like Mr. Swinford's) live a normal life with proper maintenance and oil changes, but it is a commonly known deficiency as Donnie has said. If the leak down test shows good compression, where else could the problem possibly be? The integrity of these engines is mostly in the head, if the cylinders are in good shape, money and time will be well spent on the head. A valve job with new guides and seals will most likely make this engine like new.