Many years ago myself and some friends played laser tag. We used guns from Hasbro called Survivor Shot, they were green and had better range than the old Laser Tag guns. We called them Nukems or green snot guns, the nukem term came into play because these guns would demolish the old Laser Tag stuff(in game play of course).
I did do some mods of the Survivor Shot guns. One was a Borg arm, I'm sorry I don't have any pics(If I come across it, I'll get some pics up).
I don't know what generation of laser Tag guns you want to use. The old ones used a LED which could easily be put into any prop gun. But you might have to use a belt pack to house any electronics and batteries. But one thing to keep in mind, playing these games puts the guns through a lot of abuse. I don't think a resin prop gun would stand up to the abuse. You would be better off with something from Art Asylum(plus a lot easier on the wallet, if that's what your going for).
Post any questions I''l be glad to answer if I can.