I remember Taco Hell back in the day - and, yes, they did wear these ridiculous moustaches. They haven't changed much in the past 30 years; but then that's the hallmark of a successful fast food chain - make every restaurant the same and make everything taste the same. The only thing that changes over the years is the portion size, which keeps getting bigger and bigger.
My favorite chain restaurants when I was a kid was Shoney's (because they gave you crappy comic books), Sambo's (nothing like a good racist fast food chain), Burger Chef, and, of course, the Sizzler!. On special occasions we'd hit the Steak and Ale.
But then, we, like most families, rarely ate out. The extent to which today's Americans blow money on fast food was simply unheard of in the 70s. Plus, there wasn't a fast food joint on every corner - the majority of the eats were not franchises.... but I digress.
Here's a mildly irritating Taco Bell commercial from 1978. Ever since I saw it, I can't get it out of my head - so, I thought I'd spread the misery. "Taca-taca-taca-taco Bell!"