here ya's are...
thangs have changed since '77...
I discovered this topic only today, and wow!
however, years ago, digital caliber in hand, I started measuring strings and my first attempt was with Rotosound RS66LD, and in fact the actual gauge was similar to the one reported in this catalogue: 48-63-82-102.
the Rotosound RS77 also shows a .050 G string, but advertised at .045.