No problemo!
So when he equips armor, his body is being altered? Odd... because I think by default that shouldn't happen. But I should be able to help with that as well.
Armor visuals for a model are defined by the Root Template it is using. So go to your race's Root Template. At the top of your options, there is a spot called Equipment Class. But I believe all the Flesh Golem's default to none already.
Are you talking about character creation armor or in game? In game like I said should already be defaulting to no appearance changes when something is equipped.
If you're talking about character creation, what you would have to do is override the default classes into your mod (copy/paste all the class files into your mod; you would have to follow the Wiki guide for packing/unpacking to get those files). You will then see that equipment sets are defined by race in the class file. You would create one for your race, and then create an Equipment Set stat that defines what you want, which would be blank. But make sure you make it empty for Preview; for Starting Equipment, you would still want to give them the usual bag/res scroll/appropriate potion/appropriate weapon. And don't freak when you don't find the weapon at start--that is defined thru scripting, and your start weapon is always next to Windego in that chest.