do you think politically incorrect sentiments can be virtue signals?

Yes, but they're not as frequent as leftist ones because, as you point out, those are protected by the establishment.

For example, in order to score points with some conservatives, I could denounce Jews as the rulers of everything bent on enslaving everyone, something I don't really believe.

Generally, virtue signaling or the purity spiral refers to broadcasting an opinion in order to get praise or positive strokes..