I ran the # on my bike and I am not sure if it is a Columbia.The chainring is throwing me off.The ser# is N 7982 which I came up with 1950.I can not find any pics with that style sprocket or chainguard on that year.I did find the guard on a 48-49.I have seen that sproket but can't remember where.It is unlike the Goodyear I have as well.The wheels and fenders or from a 55 Goodyear ladies bike I have.Any help will be appeciated.Thanks