Plug it in and turn it on. If it is a V54 lamp, it will be cyanish in color, if normal florescent color, it's the older pre-V54 lamp. It would work only on graded paper.
I used to have one, and when I switched to VC paper, I bought the V54. I never tried the yellow filter thing that Ronald describes, but I've heard that to introduce enough yellow to overcome the blue, you lose considerable exposure intensity.
Voltarc Tech, the new company, is in production to bring some of these back. Look for a thread on this - search for V54, Aristo, etc.
This woman works for them and can help you:
Well, so Ken jumped in while I was typing. He is one of us leading the charge to get these lamps back into production.