I would just give it some water, turn it on, and see if it starts.
If not, then you may need some jumpers, but generally on the big lasers you dont need any.
My 168 requires an interlock but it is literally a two-pin plug that says "interlock".... pretty easy to figure out! hehe.
CAn you see how many hours are on the head? Do you have a HV source (like a hene power supply or a tesla coil or something)? If so, give it a quick zap (avoid where the mirrors seal to the tube! (that is, if it is a sealed mirror tube, which I think it is))
If the gas excites when you hit it with some HV, then you know that the tube is at least gas intact.