The serial numbers on pre-war N frames never got into the 6 digits. Most likely your grips are off an N frame with the serial number S133,516 which would put it in the 1953-54 time frame. However, they should not fit the pre-war frame as well as period correct grips since the pre-war N frames had a slightly longer grip frame. Again, pictures would help the experts here help you. Even pictures taken by a web cam are better than nothing.