Prices on ebay are, at face value, often inexplicable, regardless of what the item is, or whether it's old or new. Unless you know exactly what you are looking at, it can often be difficult to tell why a certain price may be achieved or asked.
On the face of it, it might seem barmy that many twenty year old original Stradic GTMs sell for similar, or even greater, than a brand new Stradic GTM RC. Right or wrong, many people simply value the old reels more highly than the new. People like the fact that they are made in Japan rather than Malaysia and believe that the old ones are higher quality. I own the former, but no longer use them. I'm happy that they are better quality than their modern equivalents, but certain parts are now unobtainable. However, I wouldn't buy either reel, inflated price or not.
It's not always the case, but a reasonable new reel at £50 quid might not be a patch on an old reel at £60. Yes, you have a distinct lack of guarantee. You may no longer be able to get parts and it may not be in as good condition as you'd like. You pay your money and take your choice.
Caveat Emptor. Do your research, know what you are looking at and avoid mad bidding wars. It actually matters little whether the item is new or second hand.