Giok,Although it is subject to the whims of bidders, whenever I want to get some kind of idea if something is collectible, I check http://www.ebay to see if anything similar is at auction.
Checking on Spann, there were a few that came up. One was an LP from 1965, someone in England has it, but started the bidding fairly high and no one has bid on it, so I usually take that as a fair indication that everyone is waiting until the last minute, or it is priced too high to begin with.
kat