Are there two heavy machine guns in the Beta?

[EverCafe44]

I think everybody knows about the GR9 and its earlier model but what about the one on the APC. I was watching the " Half-Life 2 Theft: An interview with James Watt " video and at 12:42 there is a APC with a Heavy Machine Gun on it. I don't think alot of people know what this gun is can anyone help me out?
 The best part is the gun is usable meaning it was probably a early emplacement gun.

[PrisenShift]

Uh that gun in d3_c17_06. This gun was made in late 2003 and yeah, it was early version of Emplacement Gun. As you can see, in early version of traffic tunnel with manhacks, Freeman suppose to be use heavy machine gun on broken APC instead Combine Emplacement Gun. This gun is include only in this map.

P.S. Sorry for bad english.

[EverCafe44]

Thank's is there a specific name for that Emplacement gun?