Do you have any other OH-58 to compare with ?
If you dont find any problems in the rigging, perhaps time to consider the aerodynamic situation for a rotor turning i that direction ?
(mabe known, but as repetition
The gyroscopic precession makes the input needed to be 90 degrees before the desired action. To roll to the right, input with increased lift will be 12 a'clock in clean air. To roll to the left input with increased lift will be 6 a'clock. The air flow through the rotor is down, reducing the effective angle of attach on the blade in the 6 a'clock position.
I did'nt fly the OH-58, so I dont know how it normally reacts. If I remember right, you can sometimes feel the difference in left vs right roll command in Bell 206.
For more about the phenomenon, read about Bo105 and this issue.