I believe I just won one of the first year lava lamps on eBay (correct me if I'm wrong, Jonas) for $36.00. The base is a 2 piece and looks more copper than brass. The url for the auction is:
Yes. I believe that's one of the very early designs. There's another design that's even older, I believe. It has a switch mounted in the base, rather than in the cord.
It isn't a 1st-year unless: The cap is coppery too, the base has a rotary switch on the side, and the lava is liquid even when cold. You are correct, Fog. But this is a late-60s Century base. The globe may be a later replacement - in the 70s, the "orange/yellow" had RED wax (the 80s switch to "red/yellow" was really in name only). But either way, for $36, it's a nice buy!
That is a nice lamp and it sounds like you found a good deal. Thanks to this site - well, the old version of this site I know I also have a Century model lamp. May have paid $10 for it at a yard sale, my wife might remember. Now I am wondering how old it is too...
Look inside the cap. There might be a small sticker (3/4" x 1/2") on the side with a model # and manufacture date. Looks like you scored a U.S. Century model (model #100). I just bought the same model and unscrewed the cap to find the sticker --- says July '76.