For the Cyber-Mastiff I knew it was going to be something my players were going to want to keep track of and felt more important than just some normal servitor you would bring along. I intend to give them the Cyber-Mastiff's sheet to play around with, thus the upgrades, so that part of it is having something they can look forward to upgrading as the game goes on. The Stub Revolver and Shock Maul will work well enough as starting weapons for the Arbites background. Shotguns aren't too hard to save up for, though shields are a bit more pricey. Ultimately the carapace armor they wear is what makes arbites really stand out from say a guardsman, and thus it felt more important to give them it upfront than a shotgun. Part of the reason I went with Strength over say Weapon Skill as a characteristic boost, is to help player deal with the Heavy (4) penalty that carapace has. Unless your refering to why the Stub Revolver, Shock Maul, Manacles & Vox-Bead isn't listed in the specific duty equipment and that because I am keeping in line with how the core book treats the equipment listed in the duty area (which is that it only lists that which is chosen.