EBay is a national marketplace. There are about 50 259E's listed right now For Sale. Check out what is being asked, and even more importantly, check the "Sold" listings for 259E's to see what they actually have been bringing.
There are price guides, but auctions are real time.
Personally, I'd keep it. I don't think they are particularly valuable. But - check and see.
BTW - you spelled "caboose" correctly.