Will Call access

[rvnquest]

I have the potential of getting meet and greet passes to Megadeth, but have to check the 'Will Call' a half hour before the first band.  
 
 Can you access the 'Will Call' from inside the venue or do I need to wait outside the club to check to see if they left me passes?  I already have tickets in hand, so will not be needing the 'Will Call' for anything but the passes.

[A Girl Called Malice]

There are two box office windows, both on either side of the front doors and one is accessible from inside the building.