JD 200LC auxiliary hydraulics

I recently purchased a JD 200LC with an auxiliary hydraulic function operated via a foot pedal. The foot pedal is currently froze up so I cant try it out. It appears to me that this is a unidirectional auxiliary circuit and therefore cannot be used to operate a thumb. Is this correct? Can this be switched over to a bidirectional circuit?

Thanks for all of your help,
Dustin

JD 200LC auxiliary hydraulics