Here's a nice old Cat 12F-13K1345 refurbished 1968 model year, grader. Weighed 28,600 D333 engine @125 hp 6F/4R Transmission Built from 1968-'73
thats a nice looking unit, looks to be in very good shape.
I used to operate a 12 just like that. Im not sure of the serial number, it was different in a few ways, the air breather was at the rear of the machine, where the handel above the tail light is and the hydraulic tank was behind a sheild in the cab on the right hand side of the seat. I dont know if theses were a factory set up or what. Was a real blast to operate