If your talking about the original ductile iron Mopar adjustable rocker arms found on the 300letter car motors and M.W. motors they do vary from 1.48 up to 1.53 ratio
if your talking about the early Isky ductile iron and other brand ductile iron adjustable they vary also
RAS use to bush and correct the ratio, even increase them up to 1.62 or so, but if your going to buy a use set and have them fixed why not buy a good new better set to start with like Comp Cams stainless bushed or some good aluminum roller rockers like T&D or Harland Sharp