Yes, it is possible.
There are a few benefits if you combine two copies of the game:
1. The pool of items increases and this changes the trading aspect of competition - normally there is only one "best" weapon of each type a player of a certain race could obtain. But, for example, with two assault rifles are found and equipped by some players, all of the players may consider gaining better ranged defense (maybe more than one item).
2. It opens more combination options between weapons, since each weapon has some special skill. Some of the skills combine well with each other (like the Tail ability to increase the power of next attack) or can be used to better penetrate through armor (like weapons with an additional attack type). Combining some of those skills may lead to some unexpected or even overpowered combinations (like two mutant Tails one after another).
3. It offers more allies and thus - more options for skill combo or for ambushes. This could potentially increase game duration and variety.
► We must note that two copies of the game will not necessarily improve the gameplay - but in some small ways it could increase gameplay possibilities and make it even more fun, especially for long games with many players.