The CZ's of that era used an epoxy-like finish that was not very durable. It was replaced in the early 1990's with the very tough finish currently on them. It is not uncommon at all for one to have been refinished.
Not all Pre "B"s have trouble with magazines. The earliest ones will not take the current batch of high-caps, but many of them do. Remember, the "B" model came out in 1994/1995 or so, and is comparitively new. This one may, or may not, take high-caps. It isn't the earliest frame-design.
It is hard to know without looking, but the fact that it has been refinished does not mean it is shot out. Heck, even the short-rail 75's that came out of South Africa that looked like they had been ridden hard and put up wet (like most arms that saw long-service there) were in generally good shape internally.
I have personally owned several from that time period and they were in good shape with excellent triggers and took any kind of quality hicap. I did own a transitional model (1994) that would not take all hicaps, however.
As to buying it sight-unseen, the risk isn't bad. You could probably sell it for the same price if you needed to. It's a risk in any case.
Ash