What's wrong with this tape? Test yourself and then scroll down for what I saw. You may see something I missed.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5752928967
1. It's not on a 10.5-inch reel as the seller describes -- it's 12.5 inch. Even if you don't have the model number you can tell by the distance between the cutouts and the edge of the reel. The old style 10.5-inch reels have a distance of 1 inch. The current style is .75 inch. Also 3750 feet of tape will not fit on a 10.5-inch reel (unless you feel lucky or are really good at Jenga).
2. The reel couldn't possibly be "brand new" as described because the reel is less than half full (you can see the tape edges), it is not sealed in plastic, and the end of the tape is held down on the outside of the reel.
3. It's from 1985 -- a very bad year for sticky-shed. This is the very old pre-1986 style of box. It's a good example of what not to buy if all a seller shows is the picture of a box.
I kinda doubt the seller is trying to deceive anyone -- too many nice pictures. It's just an example of what else to watch out for on ebay -- seller ignorance.