Brass gear is for a roller cam, no doubt about that. If you have a flat tappet cam, don't use brass.
Total rebuild because you lost the brass distributor gear??? Gimme a break, baby it my a$$. Drive it like you stole it! Change the
oil, change the filter and let her rip.
Other causes of early dist gear failure are incorrect clearance on the dist drive shaft and the engine block. HV or High Pressure pumps also increase wear. Bad bushings in the dist itself will cause premature wear.