Well, again AFAIK, there are no plans for even trying to replace barrels or bolts with such materials, so the same question still stands, just slightly re-phrased: Is there some mention in the books that barrels and bolts are non-magnetic in the 2060s?

In the section I mentioned it says "Note that in 2061, most metals are nonferrous, semimetallic polymer compounds, including those used in weapons and cyberware."

Okay. In that case, magnets would certainly not take away any weapons, cyberware, armor, or anything else.

GM has the final say. Also, how well do you trust your local arms dealer? Maybe the cheap knock-off copies do have metal parts...

(or alternatively, 'meh...')