I think you could justify giving the wolves some heavy machine guns, as they would likely be able to carry heavier loads. The high rate of fire could be used to compensate for a lack of visual acuity, since canines have a worse eye for detail than humans do. Having this level of firepower while maintaining above-average mobility would be a game changer combat, particularity in urban or jungle warfare.
Alternatively, you could say that the wolves prefer not to give away their position, maximize the advantages of their night vision, and avoid polluting their air with gun smoke by giving them sub-sonic projectiles like bows or cross bows. Sure, this wouldn't win a full-scale fire-fight, but it might make them victorious in a war of attrition.
In terms of modifications for existing weapons, weapon straps and ammo belts/pouches that will stay with the werewolves while they shape-shift would likely be appreciated. Maybe the smell of gunpowder would be bad enough to warrant different gas vents on weapons. But the most needed modification would definitely be silencer, and not Hollywood silencers. If firing a gun hurts a human shooter's ears, it would be unbearable or even permanently damaging for the sensitive ears of a werewolf.
As a whole, I'm picturing a eight foot tall, seriously hairy Rambo-wolf with a sensible pair of earmuffs. This is your warrior.