GM drilled the casting for whatever vacuum connections the individual applications required.
If you have extra connections, it's easy enough to cap them off with commercially-available plastic caps.
If you need vacuum nipples that aren't there...drill the casting in the proper location, slide in a length of seamless steel brake tubing in the proper size, sealed with threadlocker. Don't try to remove tubes from one TBI for re-use. You may get the tube out...but you'll maybe wreck the tube in the process.
Best if you put the tubing into a double-flare tool, and just start to make a double-flare. Don't squeeze it all the way, just enough to distort the end of the tube to make a "bead" so the rubber hose doesn't slide off.
