1962 aluminum sliding door replacement rollers

Can't find any markings. The house was built in 1962 by an architect/engineer. The sliding glass door is original to the house. It is 2-panel 10' wide, 78" height. Don't know what rollers to order if these are even made anymore. Any feedback would be much appreciated. We really want to keep the slider. A new one would stand out like a sore thumb in this beautiful original mid century house. Thanks!