guessing it's a design meant to slander a particular gang.. that's an 01 in the slash, right? dont they usually wear a 1% on their colors? yeah, I'd steer clear of replicating this or even dealing with the customer who requested it if I'm right.
I think the 81 is a reference to the Oakland CA chapter of Hell's Angels.
I doubt the font has much significance since it is only a poorly matched choice for the western style font used by the group. You could use any number of western style fonts and it probably would not matter.