I don't think that is a 1948. A 1948 model had a gooseneck steering head, which changed to the flat plate style in 1949, on the Model K. You also have the 2" wide rims, which didn't start until the later 1949 Model L.
Look under the steering head, is there a plate with a frame number on it? It may be hard to see. If so, post the number and we will see if we can get you closer to the actual year.
Also, is there another number under the compression plate cover on the left side of the motor? If so, what is it?
Rick