Thanks for the response. Those were my thoughts exactly, but the serial number format certainly matches Centurion, but I can find no reference to any frame from them with these dropouts and/or a braze on front derailleur. A close look at the head tube shows the faint outline and screw holes that could match a Raleigh badge (three holes in a tall triangle) , but the serial number format doesn't match anything I can find for them. Does anybody know if Centurion provided frames to anybody else, or another company with this format of numbering? Did Centurion ever do 'custom' frames in the manner of Panasonic?