I tried it to 3D model. Guess it is not about layers. Bolts are still invisble.
I did it inside the drawing and it worked.
( Earlier I did the "Menu - Format - Layers Visible in View" when in 3D-model. )
When a drafting view is created, the layer visibility is set to the current global layer setting. For instance, if your bolts are on layer 2 and layer 2 is set to invisible when the drafting view is created, nothing on layer 2 will be visible in the drafting view. If you later change the global setting (format -> layer settings), it won't have any effect on the existing drafting view; you'll need to use "layers visible in view" to make layer 2 visible in the drafting view.
I don't suggest using "layers visible in view" in the modeling application. In general it leads to confusion when applied to modeling views. (Dear reader, if you use it in modeling as part of an established company standard workflow; note that I'm not talking to you).