Those came out in the early '80s (my Vintage Series '62 Precision which I bought in April '83 shipped with a set of the Studio Bass flats). The rounds were the stock strings on non-Vintage Series basses at the time. They were gone from the line around the time that CBS sold the company to FMIC I think. For $10, as long as they've not corroded over time, it's worth a shot. Just don't get hooked on 'em and then go crazy trying to find more!
Spelling, grammar, and punctuation matter!
"Without space, music is just noise piling up on itself." TRK
"Don't play your instrument, play music." Feral Feline
Lakland Owners' Club #248