Not sure if this is common knowledge but I only found it out last night.

If you hold genuine copies of other Battlefield games (for me BF2: Deluxe & Heroes) you can get 2 extra guns for BC2. These being the M1 Garand & F2000.

If you go here then you can get everything sorted:
http://www.battlefieldbadcompany2.com/veteran

its kinda common knowledge , but at the same time it's a bugger to get activated......

took me about 2 weeks of hammering that site b4 it stuck and issued me with the garand

oh yh f2000 is a special unlock for bc1 not bc2

yeh, its a shame the garand sucks ass when up against any sort of automatic

it didnt work for me last night. but then i gave my Cd keys to a guy on EA chat help and he did it all for me

if am not mistaken you just get these guns earlier - you can still unlock them without entering any codes