Your mudguards should be a flattened ‘D’ section, and might have a rib down the middle, but some time in 1949 they changed to a plain profile. If you have the original guards or can access some originals, make a carboard profile of the cross-section, and the two radii, and also measure the overall lengths front and rear. Then drop a line to Renovation Spares (details in Old Bike Mart, etc.), to see if they can supply. If you can get a couple of ‘blanks’ you will then need a tin basher to make the indents for the chainguard, etc.. My 1950 Flyer had a slight flare to the front of the front mudguard, but I have seen them without. Good luck !