My vote: (Most probably) EIR (early ones had BRW) back and sides, and (most likely Sitka) Spruce on top (with tinted lacquer, as Sandy pointed out). While not a definitive test, I have found that much, if not all, of the Western Redcedar in use in higher end guitars in those days has impressively close or "tight" grain, almost to the point where you can't distinguish the grain lines. Of course, you could attempt the "fingernail dent" test on the underside of the soundboard - Cedar dents by looking at it, while Spruce is tough stuff.
There is something of a general consensus regarding the use of Spruce as opposed to Cedar. I say general, as it isn't a hard and fast rule. Cedar soundboards are known for tonal "warmth", due to their inherent bias toward enthusiastically reproducing the midrange frequencies. Mid's are more pronounced, hence Cedar's popularity with instrumentalists. Spruce tends to be less vociferous in the midrange, coincidentally making room for the human voice in the mix. Spruce is more "balanced", low to high, hence it's popularity with singers.