Very uncommon rod, to be sure. These could have come from a 1967 Camaro w/350 engine. Unfortunately in this case, rare does not equal desirable.
In any event, I'd be swapping them out ASAP for a set of 3/8" rods, unless it's a stock rebuild that won't see any racing.
I have a set of ARP 11/32" rod bolts for the SJ rods, but I don't know if they will be a correct fit in the dimpled SBC LJ rods you have. If reusing them is planned, I would look into the SJ 11/32" bolts as a replacement, along w/having the rods resized after the bolts are installed.