Test was being played with as far back as 1938...
http://endo.endojournals.org/content/23/2.toc
There was a book about it also in the late 30's (test therapy), so Reeves could have used. No one knows..
Yes, synthetic test was available in the 1930s
But I'm sure all the York guys, including Grimek all knew and had access to, but due to their deep moral fibres, and cast in stone iron resolve, solely relied upon God-given genetics and pure hard work-ethic, shunning such advances in the supplementation of muscle-building.
Please understand, steroids were not immoral, illegal, nor cheating then. Only around the 60s did weider and lurie start the propaganda, to go along with moral issues. What I'm saying is they were doing "nothing wrong". But obviously, post 1982, steroids became evil, and NOBODY would ever admit, and if too obvious or caught out, they'd say they took a little once, deep into their career, it did nothing for them, and they only did it because everyone else was.
And that, is how pearl(5mg nilevar once), scott(5mg dbol once) park, reeves, grimek, became pure, unadulterated deities of the physique world. Such genetics and what morals. Wow.
There is no way they would ever admit it. Just like if you go and ask phil heath or jay cutler now, they can't admit it, and won't.