They were armed with two blaster cannons and a concussion grenade launcher.
Several Mark 1 droid walkers were stationed on Galak Fyyar's ship, the Doomgiver, during the Second Battle of the Jedi Praxeum. These were all annihilated in the ship's destruction. Some units were also garrisoned at the Cairn Installation in the Lenico Belt, but the fate of those remain unknown.
In the Star Wars: Jedi Knight II: Jedi Outcast game, the walkers' weapons referred to as blaster cannons are the same in appearance, effect, and damage as Kyle Katarn's bowcaster.