Yes 1980 it seems, based on the original still-sealed cube(s) that one of the sites is selling.
I am glad you still remember dodecahedron
I figured that being a mathematician, you might have had interest in the Rubik's cube.
A few years ago, I hadn't done speed cubing in many years (I always did it for fun; I only ever did one contest, and it was because a local audio/video store was sponsoring it. I was lucky enough to win (an Atari 400 PC) thanks to the way it had been scrambled); anyway, it took me a bit to remember the algorithms for certain portion of the solution I use. I was a bit rusty to say the least.
I still only play with the cube in spurts, sometimes not touching it at all in more than a year at a time.
The best part is that a friend in school back in 1980 or '81 found out a way to do a certain piece in 8 moves instead of the official solution's 22 moves, to accomplish the exact same thing.
Since that part can be repeated three times, you save 42 turns, which translates into a lot of time in speed cubing.
I do the top layer and sides using a method I developed myself, the rest is from the official solution we found at the time in a newspaper article (I don't know if I could ever have figured those parts out by myself), with the exception of my friend's 8 move trick (as opposed to the 22 moves used in the official version).
I think my times, while apparently very impressive to the average person (1 min 45 secs or less, depending on how it is mixed) wouldn't hold up at all in official world competitions - I noticed last night, while looking for the cube, that the top competitors in the world (many from the USA) take under 30 seconds EVERY time! Now that is impressive!
Maybe I need to learn a new solution or two, although I just do it for fun anyway...