Speedway fork question

I just took apart my forks form my 71 speedway shrike the springs are broken so I found nice replacements form FARM AND FLEET my question is are the sels at the top to keep dirt out or oil in? the don't seem to be setup for oil but they call it HYDRO RIDE in the brochure
Both. They did use oil if I remember correctly. Atkrider told me to prevent leaks to just grease the legs up. Thats what I do
Thanks for the tip grease,, FARM AND FLEET is a big farm store out here they have all kinds of stuff to fix farm machines so shafts collars u joints springs and stuff like that are there also any type chain you could need