I had one like that....
That I gave away in my barn clean out. I received it as a trade in from an old lady, when I had my store. She had said that she bought hers in 1980, and the base was indeed dated 1980. Mine had the same blue base, same handle, same bag, and a black cord, but mine had the ESP style hood with a headlight. I would take a guess and presume that, that one is from around the same time period.
Hope this helps!
Phillip