Just curious if the pre-war zinc 302s are any more or less collectible/valuable than the plastic 302s. They are older and rarer, of course. Or is it just a case of "one man's trash..."
Generally, metal 302s bring more money so to say. I prefer the metal body ones myself. As it reminds me of a pre-war phone vs the post war. Again just MHO. A rare one would be the 1937 model with the shorter & wider cradle ears. These were designed with the E1 handset in mind, and a #4 dial. RARE. I've only seen one ever for sale. Another way to tell is the vent screen behind the cradle handle(lack of a better word).
The zinc phones do tend to bring higher prices, inspired I think by their being the older of the two. From a refurbishing/restoration point of view, each has their good and bad points. The metal phones almost always have significant paint loss, and top-quality repainting is expensive. (and budget painting, i.e. Krylon, just doesn't last) The plastic phones, on the other hand, tend to be fragile. Shrinkage of the housing has resulted in cracked corners on many examples, but if you find a good one they shine up nicely!