Baking and export problems

I just created this deagle model, and I want it to be used in game development. I did the baking a lot of times, tried different ways, but when it finally came to unity, it looked flawed.

It is supposed to be all white/silver looking.

To bake, I selected each material in the material slot, then click that select button so the corresponding faces are selected. Then I pressed U and selected unwrap. After that I created and named new image for baking, and in the node editor I added an image texture node with that image. Finally I clicked the bake button. And it appeared to be baking properly.

I would like to receive some advice on how to bake properly and make models usable in other application or for other users.