I'm not confident it would, but just spitballing here, if Company X consistently posts a bunch of below-market salaries, and then/also hires an awful lot of H1B folk for the same positions, you could probably do an analysis a la opensecrets that could show a trend.

I expect this would depend on H1B visa counts at least be public information. I'm not sure that's the case, and I'm not sure if it should be.