Zak
The kit originally sold for $19.95 in 1970 (big bucks way back then) . If you use the "Search the community" button here, I posted pictures of this ship model in August 18, 2012. (I can't figure how to repost them to this thread: Photobucket, which holds all my Yamato pics is a disaster, can't seem to move them to this site).
As to the models worth...it depends on the kit's condition but more importantly what someone is willing to pay for the kit. It's more of an un-built toy than a model. The detail is sparse or non exsistent, and the detail that is present appears thick and clunky. If one compares the Paramount model with a current ship kit it's obvious the tooling is dated and rather crude. I think is was offered as a "super bath tub toy" right down to the metal screws to hold down the deck.
I hooked up the radar and searchlight feature on my model, as well as the motor: it runs well in a calm pond or swimming pool.
Still, in it's day, the kit was pretty cool, I believe it was the largest plastic ship model for the time(a little bigger than the "Blue Devil" destroyer by Lindberg). I did a lot of rebuilding on my Yamato in an attempt to make it a little more contemporary. Painted and detailed and with enough room for an R/C set up, the Paramount Yamato could be a nice pond model. I still have my Yamato, it's 43 years old!
Good luck!
Mike