they are filled with an oil yes... if its leaking it will be time for a new mount soon!
As i was replacing the waterpump, i noticed that there was oil underneath the engine mount. Do our mounts come oiled or is it a solid bushing? im not sure if it was oil or power steering fluid, as i had to shake the reservoir around a little bit.
I know your looking for a passenger side mount.. but I do have a drivers side track density 034 mount for sale...