The pulley on the mechanical tensioner does come off, but matching it up is difficult. RealOEM nor PenskeParts gives a part number for the pulley. One of the things that happens with the mechanical pulley is that the spring itself squeaks as the belt goes around. You can put a new pulley on, but the spring still squeaks and you can go nuts chasing it.

The hydraulic tensioner gives a separate part number to the pulley, and this pulley does not fit the mechanical tensioner.

The pulley is $45, but the entire assembly is $60, so I suppose the point is moot. And, those are prices on RealOEM.