HL1 uses impulse 101. But you can also add each item/ammo individually.
My half-life game had a glitch. At the part where the assassins turn out the lights, beat you up, and then throw you in the trash compactor, the lights stayed off forever and the level never changed. I had to change the level manually, then use the console to give me back my HEV suit and possibly the crowbar.
And before this, on my previous install, there was a glitch where the only weapon I could use was the revolver, I couldn't even change the weapon through the console.