I was talking about the arm-mounted Fuel Rod Gun...Cannon...whatever on the Hunters. Seno was talking about the Fuel Rod Gun...the yellow one in the bottom right of the picture.
You can do that but you wouldn't get the skeleton for it I don't think. I know you can download the skeletons for 3DS Max. Maya 2008 also has templates as well.
I could give it a try. I'm part of a 3D Graphics community and there a few people there who have done Spartans and Sangheili so I'm sure I can ask them for weapons templates.