The broken boss already has a Heli-Coil installed so it should be OK as is.

The clutch piston lip seals being discussed aren't that much of a problem, the rear seal is fully visible during the piston install and the lip can be "nursed" into place with any rounded object; the front seal isn't visible and is a little more tricky but, since yours is a '75, it will have the seal with the short lip (left in the pic below) and will usually install with a firm straight push (well lubed, of course).