The crankset on the eBay Team Miyata isn't original. The frame is probably from 92 or 93.
The red Pro Miyata isn't from the early 90's, it's either an 85 or 86. An 85 would have come with a Suntour Superbe Pro group and an 86 would have come with a Suntour Sprint group. I have one of the latter.
All of these are great frames. IMO, the eBay listing is worth that price, though, considering it isn't all original.
I am 5'8" and my Pro Miyata is a 54cm. It fits me, but sometimes I wish I could drop the stem a little more. A 52cm would probably be better for me.