I don’t think it matters whether you remove them or whether the machine shop removes them. The more important thing is to make sure the machine shop does not install the new plugs. Once you get your block back, you want to be 100 percent certain that all of the machining junk, sludge, dirt, build up, is scrubbed out of the entire galley, both sides. That takes a little time, lots of hot soapy dawn and a long galley brush. Once clean, really clean and dry, then you can install the plugs. And truth be told, even if the machine shop tells you they are clean, you have to be 100 percent sure. And that requires you doing the cleaning.
For an install tool, order a fuel pump rod for a small block Chevy. It’s the perfect size with a nice little bevel on the head.
