Hi! I have quite a number of CWC (Cleveland Welding Company) frames and bicycles and all have been correctly dated and logged by a man that is accumulating CWC data in hopes of eventually having a website for it. Nowhere in CWC production is there a serial number with a 4 digit numerical suffix. From 1935 to the late 1940s all serial numbers started with a single letter followed by a 5 digit number. Starting in 1948 suffixes were added to the same serial number arrangement starting with AC, ACW and CW. In 1952 the last two digits from the year of production followed a Cw suffix - i.e. Cw52 for 1952 and this lasted till the end of CWC production in 1956. So I guess the long story is with that serial number it was not manufactured by CWC. Since this is the only company I collect that is all I can tell you. Hope that helps a little.