It depends on.. everything, but would usually be fine. It depends on current, and what the material is, how much of it there is (in terms of like cross sectional area) and whether theres something worse in between where you start and where youre going. Like, if you attach to a 1” steel square tube you know what that is but you dont really know if at the bottom it joins the next piece with only two welds that go halfway across two sides. That would be 1/4 the cross sectional area if we’re winging it, a ‘bottleneck’.
Ive heard approximations that steel is like 14-30x worse as a conductor than copper. So if for example youre looking at a wall spar or stud abd imagine it as a piece of copper 1/15th the size, you might get a rough idea. Vehicle framerails are usually big enough that a piece of copper 1/15th the size is still a big piece of wire, but once you get up into the body structure thats not generally true and you have to think about whats in between. For example, if you screw down to a truck cab or bed thats suspended on bushings, you have nowhere near as much ‘conductor’ between the body and frame as what you think. For example, A newer tahoe i believe has a battery that grounds to the firewall which means the cab itself has a fullsize ground wire which grounds it to the frame. You can ground anything to that body because the ground path is designed for hundreds of amps from the starter motor. An older chevy truck might have a battery negative that makes a pit stop on the frame before continuing to the engine block but only a 10 gauge wire goes to the fender/body. So, it depends.
If youre talking really low currents, itll almost always be fine. Big currents, you gotta be picky.