The construction guy isn't called gus...the forklift guy is, and they're diff. people. The Asheep team got it wrong, the construction guy is actually the old barney model...that's why all the textures are prefixed with "BARN_". They changed it to the current LD barney before the game was released, if you look on the HIT website, it has a pic of the old alpha/beta barney somewhere.
Construction.mdl was never used in HL as far as I know, but Gus the forklift guy was used in the intro.