The shorter the wavelength the more fading is the way I think it works. So yes, if you leave a massive light like that on all the time you might see fading. I would go with something more like the LED DJ bar in the link below and use it when you are in the gameroom or having a party and just not 24x7 otherwise.

They have one of these on either side of the bar in a local strip club. Mounted way up high they really make the carpeting pop in a huge area. The owner was bragging about finally being able to see his expensive blacklight carpeting. He shut the LED bars off for me and left the other dozens of CFL and incandescent blacklights running. The carpeting was absolutely not lit at all until he turned the LED bars back on.

http://www.amazon.com/American-Supply-Eco-Bar-Plus/dp/B007YD02G8/ref=sr_1_2

LEDs are way narrow in spectrum and don't give all that much effect if you're looking for reactive materials to go with it. I did a ton of research into this when designing my gameroom lighting. The conclusion was basically what you'd expect... LEDs are more reliable and cheaper to run now but they don't have nearly the effect of a good old fashioned 4' purple tube. To get the same wide band of UV with LEDs you'd have to put in a ton of separate fixtures each with a slightly different wavelength in order to get the same range as the tube. Doing that with LEDs would be extremely hit or miss, if you could even find LED strips in all the wavelengths you want, and it would also be ridiculously expensive.

I also think this question is probably overthinking it. Unless you're going to run your black lights ten hours a day there should be barely any fading on anything in the room. People tend to forget that an arcade is open over 100 hours a week and a pin will sit there for years.