What's the diferrence?

Hello, how are you?
I wanna know why in some Cross Fires some guns are for GP and others are not, I'll use as an example, the gun MSG90, this cross fire it is a Black Market weapon and in the European Cross Fire it costs 50,000 GP in the Item Shop.

It would be a good change and put just weapons "camo" or "adv" to win in the crates and the normal (original model) you put guns for sale in the Item Shop?
I think it would be nice to create a greater diversity of weapon in the game and leaving more options for players who can not afford to pay a lot of ZP not to get anything?
Thanks, LiquidLucas.