I would think someone on here will be far better placed to answer your question then me, but to my knowledge the hull mounted gun would be the 'swiss cheese' look but the coaxial i am sure i have seen like that but also in some sort of sleeve.
Might also help but i tend to always use the following when looking for reference material tank wise and they may be of some help to you.
Tank encyclopedia
Military Factory
War thunder (can be useful for decent models)
Also if you need any more Stuarts consider the
rubicon model its a really nice kit.