Doesn't matter. The price quoted to you was the price per ounce. Ounces were the same size in 1977.
The candy bars at Vons are the small ones. They are the 1 oz size and the price is $1.29. When I was a kid they were 5 cents for the one ounce candy bar. That was the deposit on a large coke bottle. I could get a candy bar for every 24 ounce bottle I redeemed and a candy bar for every two 12 ounce bottles. They didn’t have 16 and 32 back then.
I generally pay $5 for a 4 ounce premium bag of 1/4 ounce Ghirardelli dark chocolate squares. That’s $1.25 per ounce.