Looks like the beveled seal might just be more of a wiper and not the actual seal. The actual seal may be the "O" ring underneath. The wiper just insures that no external debris gets to the "O" ring seal and damages it causing a leak. But that's just a "guess" on my part based on the hydraulic cylinders that I work with at my job.
A hydraulic cylinder repair shop may be able to supply a generic style wiper seal that may or may not look exactly the same but still performs just fine. That's where I go to get most of the parts for my tilt/trim cylinders and manifolds. Usually cost less that $3 for the "O" rings but they have a minimum charge of $5. Still a pretty good deal.
