I thought, If you did dashboard or turn your xbox off, Or do something like that It would be gone. I also thought you couldn't use it online but I don't know that for sure.

Hope I'd gave you some more info ;)

yeah i dont want it pernament

Ok I do not have a JTAG so i cant host a lobby for you but here is all the info about the 4 perks and 3 guns:
The forth perk replaces the equipment slot and the third gun replaces the equipment slot. Due to this you cannot have any equipment or special nades. In my understanding though you are able to change the primary and secondary weapons to any weapon you want that you have unlocked after u get the 3 guns and 4 perks mod. The problem with this is you can only have a normal secondary weapon like a pistol, launcher, etc. instead of a M16 or a normal gun like the mod gives. You can also change the perks except for the one in the special grenade slot, and they can be changed to any other perk in that specific perk slot. The downside about the mod is the host picks the weapons and perks for each class and for each person, meaning if in the first class it is a M16 as primary, a Intervention as secondary and a RPD as equipment then everyone in the lobby has exactly those guns and the same with perks. And also they do last forever until either they somehow patch the glitch and makes them go away, which is u probably have a better chance at winning the lottery than this happening, or if you change everything, and if you prestige after the mod.

I HOPE ITS NOT PERMANENT.