Hyster RC150 Main Hydraulic Cylinder Question

We have a 1958 RC150 that we are trying to get going again. It's had a rough life, with the past 10 or so years spent outdoors, just sitting. We have the main lift cylinder apart and what we found is confusing. The internals consist of the main ram and two semi-circular wear rings that mount in a groove about 1 inch from the bottom of the ram. There are no other seals at the bottom of the ram. Based on this, it would appear that hydraulic oil is expected to leak past the wear rings at the split joint and fill the area above the rings. That is not like a normal single acting cylinder. There is a bleed at the top to remove any trapped air. From this I surmise that oil above the rings is intended to act as a speed governor during the lifting stroke. The only problem I see with this is that the oil can always leak past those rings and with a heavy load on, if the lift is stopped and held at one height, the ram can slowly lower due to the weight of the load as fluid gets past the wear rings. Are we missing something from our cylinder, like perhaps a separate sealing piston? We took the ram to a hydraulics shop and they said they had never seen anything like this before. Thanks for any light you can shed on this. regards, Rob