Clutch Slave Cylinder Question

[PG45er]

When I boought my 1977 FJ45 it had an OEM clutch slave cylinder kit in the glove box. I planned on using it but it only has one seal on the piston. The bag is unopened,

so one could not have been removed. The old slave had 2 seals. I'm guessing it's missing from the factory or would this be a change up?
Any input would be appreciated ed. Thanks

 

[3_puppies]

IDK but these in this thread have 1

Early Slave Cylinder - rebuild kits? (1958 to 1965)

 

[PG45er]

IDK but these in this thread have 1

Early Slave Cylinder - rebuild kits? (1958 to 1965)

Interesting, perhaps they went back to one seal but used the same 2 seal piston? I'll try it and just keep a close eye on it.
Thanks 3 pups