Yup, measure each valve lift. they will be all about the same except 1.5 times stated lift of cam. Or just do "visual" if it ate it enough to make noise you would see the rocker not moving much. If you ate a lobe i dont think it would make much noise as its just not lifting any more.
THe only time i heard a cam make noise or "rumble" was in a 66 thunderbird. whomever did the timing chain didnt read the instructions That the cam "shim" is not needed as its built into the cam gear. cam walk was about an 1/8 inch! it moved so much the lifters hit the bearing surface and took huge chunks out of it.Not to mention that the lifters had chunks taken out of them.funny part it really ran ok. i had a rumble like bad main bearings , but too high up.