This week's Faygo flavor is Old California lemon & lime.
California became a state in 1850. And since this is an "old" California flavor showing a Spanish mission, I'm guessing this depiction of Senior Lemon and Senorita Lime performing their Flamenco Beverago took place sometime during the 1870's. After all, weren't bell bottoms popular in the '70's?
The can is from 1977 when Faygo was celebrating its 70th anniversary.