Dave, this is confusing because there were two Kansas City GM plants. The one in Kansas City, Missouri (code K after 1965) was also known as the Leeds plant, probably for some neighborhood, industrial district, or suburb nearby. The Kansas City, Kansas plant (code X) is also known as the Fairfax plant. Looks like GM had to use alternate names to keep the confusion down.
Each plant did not build the same brands or body sizes each year. This will make the plants seem to come and go if scrolling through the years of a particular make and size of car such as the Buick GS.
The Leeds plant was producing Buicks by about 1948 or 49, based on VIN nos. This GM/Fisher body plant was built in 1928, and began prodcution in 29. It was closed sometime in the 80s.
Our site shows the Fairfax plant (code X) listed under 1965 serial number info. It began as a WWII B-25 bomber plant for North American Aviation. GM made it a Buick-Oldsmobile assy plant after the war, not exactly sure what year. One article on the Web indcates the Fairfax plant was constructed after 1985 on an abandoned city airport site. That leads one to believe this plant was built to replace the old Leeds plant.
It remains a puzzle too as to which plant is referred to on the body data plate. The assumption is it would be the Leeds plant, but this may not be correct.
[This message has been edited by TODD (edited 12-05-2001).]