Cast in, definitely pre-65 then, according to your rules. (I figured this was older that me; I'm a '64 model.) In fact, as I was dismantling everything for cleaning last evening, I was unable to budge the powder cam from its holder (after removing the screw, of course). I am considering refinishing the base, as it presently has a crappy silver paint job. Recommendations are welcome; my first thought was bead blast and anodize, though I don't where where to have the latter done yet.
-Kirk