Confused by controls

[nightrider1470]

I am trying to setup my G13 keyboard for metro 2033 it says on the controls
http://www.allgame.com/game.php?id=67826&tab=controls

1 Key knives
2 Key revolvers
3 Key machine guns
4 Key special weapons
5 Key grenades

What are these keys? as setting the "number keys" doesnt work

 

[Confused]

I'd guess at the number keys above the letters, rather than the ones in the numberpad.