I just bought a 77 Industrial, and the identification tag is confusing.  It appears to be a 1952 77 Industrial with a Lull loader, and all of the correct equipment for an Industrial tractor.  However, the serial number is 273975, which is a 77 standard serial number.  The specification number is 77-7115. Can someone help me with what this spec number calls for?  One serial number list that I have says no Industrials built in 1952, so I thought a standard might have been pulled out and rebuilt as an Industrial, but the other serial number listing that I have shows numbers built in 1952, but none in 1953. The tag is fastened to what appears to be a cab heater under the dash, but there is no cab.  Any help is appreciated, Thanks, Terry.