The bottom markings and patent number indicate a lighter manufactured between second run of 1936 and the first run of 1949, excluding a large part of 1942. Depending on the number of barrels on the hinge, the shape of the lighter suggests it was manufactured between 1946 through 1949 because of the rounded lip and "canned" or indented bottom. However, I'm not an expert, and during my collecting of Zippo lighters, there have seemed to be variants from year to year that aren't textbook. I can promise it's pre-1950 because the patent expired and a new patent was pending for a few years. I can also promise it's post-1935 because that patent didn't show up until late in 1936 production. SOME (others say MOST) 1942 Zippo lighters have an error on the patent (203695 rather than 2032695), but I believe the canned bottom excludes 1942-1945. As I said, depending on the hinge barrels, which I'm guessing is 3, I would presume you've got a 1946 to 1949 lighter. I've never actually seen a 1938 to 1941 Zippo in the flesh, but apparently a slight variant to the typical flat bottom seen from early Zippo production through 1945 exists, making the bottom somewhat convex with a slight lip around the edge. I can't be certain from the photos, but your lighter should be more concave on the bottom. You've got a heck of a find, one I've yet to make, though I've only been detecting since September of 2006. An early Zippo is definitely on my "wish list," no matter the condition, and you've got one that seems mighty fine. If your hinge isn't the 3-barrel variety, you may have one the of the "Odd-Balls." A question, are you going to clean it? Thanks for posting what, for me, is an extremely fun find.
Ross