Can anyone out there tell me when the oil filter that mounts directly to the oil tank first came out. I just finished restoring a 1948 Panhead back to original. I have an old photo of the bike from late 1948, early 1949, that shows it with the oil filter. I have had other people say that it is impossible, since the external oil filters didn't come out until mid to late 1949. Would it be correct for AMCA judging with the tank mounted oil filter?