A couple other things to note on the early postwar Dx’s. The rear dropouts are thinner gauge metal the the 47 and up bikes. If you can compare to bikes side by side the difference is obvious, otherwise you need to measure them. Also, the front chain guard mount is thinner gauge metal and tends to be attached less securely to the bottom bracket. I know this is true of the bikes with the upper rear fender mount that is tubular rather than the later channel style mount. These are observations from seeing several of these bikes personally, and by several I mean at least 10 owned by me and a couple friends.