I am with Blkjudge here. Leave it be, the body mount connects the body to frame.......looks still connected. It does have a rubber bushing, but the bouncing properties of that probably went out with Nixon.
It has stayed attached, so it likely will for many years. Just inspect it now and then, if one comes loose then you may be forced to do them all. But likely they will all stay put and a new one probably won’t be any tighter.
PJ’s Frame brace may be something to consider.
One of the guys at the cruise in was talking about putting in a new dipstick in a Pontiac 461 that was recently rebuilt, because he did not think the proper top arrangement was there, they differ some AC cars, non etc. Me aand a friend who had just finished building my 461, said for the. Love of Pete, leave that dipstick be. If you break it you will have to pull the engine, the pan etc.
As Johnny Cash sang at Folsom Prison in the last line of the song “Cocaine Blues”........
“Come all you guys listen unto me, lay off that whisky and let those body mounts be”