Are these mounts OK to use??

The rubber does look good, these are brand new mounts, I had never thought of tack welding them, that is a good idea, thanks! It must be a standard practice I guess to put the cuts in, considering they were on two sets I seen so far, when tacked I will feel much better about them. The shumachers I am aware of, just want to stick with rubber due to vibration with the poly. I could fill the voids on this mount with polyurethane from a tube, not sure if this would be any "better" though?