From the oliver gang serial number list it shows about 3000 produced 1936 to 1939,total run went to 1948 13000 approx. There are no cockshutt records [they were destroyed in early 60's ] and none has found any records of what was sent to cockshutt . Best guess that anyone has is 30 % were made as cockshutt . I have found one 80 rowcrop cockshutt here in ontario so rowcrop cockshutt 80 would be rare. Most 80 standards here are cockshutt not olivers.