However, I do recall that candy bars went through a sea change in the 1970s, many being discontinued in favor of new concoctions (where did Mountain Bar disappear to?). Others were shrunk in size because of the increasing costs of sugar, cocoa and even the wrappers. What you got for a dime in 1970 was a lot more candy than that same dime bought you in 1975.
Nixon's wage and price controls may have played a role in the size of candy, also. One of the ways manufacturers were able to avoid running afoul of the law was to repackage the product as a "new" size and price it accordingly. I think the large size Snickers came out during the early 70s and may have cost a quarter. They're around 79 cents these days.
Perhaps one of our FReeper candy afficianados can fill in the details.
Mountain Bars are available from Amazon.com's Gourmet Foods section, $16.80 for 24 2-oz bars. Also available in cherry version.
Mountain Bars still exist! Cherry, Vanilla and Peanut Butter.