Can't find it directly yet, but if you look in the AISC 6th edition (1963), table 1.11.4 on page 5-31 lists the allowed shear per stud anchor based on the strength of the concrete. You might be able to back into the Fy using the allowable shear on the gross section of the stud as a minimum capacity of the stud section (section 1.5.1.2) Fv = 0.4 Fy (concrete controlling). This should get you in the ballpark.
I did a little more digging and found an AISC engineering journal article from April of 1971 by Ollgaard, Slutter, and Fisher titled "Shear Strength of Stud Connectors in Lightweight and Normal Weight Concrete. It said that the tensile strength of studs varied from 62 to 82 ksi, but in some cases was unknown. They give a bunch of test results, and then at the end of the article give the following as a recommended design equation:
0.5*As*sqrt(fc*Ec)
This is very similar to the equation given as I3-3 in the current steel spec. The major difference is that equation from 1971 does not have a limit based on steel strength.
They also give the equation that the ASD provisions of the 1969 spec are based on, and it is only a function of concrete compressive strength, and is only valid up to 4 ksi concrete compressive strength. This equation is 37.45*As*sqrt(fc), with fc in ksi. The safety factor was 2.5.
