Comment by han enderman:
I know nothing of Decca pressing plants, but I have images of Decca 3913 (Nat Brandwynne) that both have a small "o" in the runout opposite the mx.nr. In this case, mx at 2 (actually the bottom of the stamper) and "o" at 8. Also on a later pressing of 3905-A. And on 2 copies of 3893. Isn't this too frequent for a West Coast pressing ?
Comment by xiphophilos:
I've added the runouts of my copy. The little o (actually looks more like a small zero "0") is probably a pressing plant ID. My guess is that it's Decca's West Coast plant in Los Angeles, but I have nothing to prove that. Does anyone else know more?