The original exhausts on the 2.6 and 3.2 (can't speak for a 2.2) had angled stainless tips which looked quite neat. Replacement GM back boxes had tips, but they were cut straight, and weren't stainless, so they rusted quickly. Aftermarket exhaust don't seem to have tips.
Whenever I have replaced a original GM back box which had the angled stainless tips, I have removed them (they are only held on by a couple of blobs of weld), and they fit quite neatly over the tips of the replacement. I hold them in place using few blobs of Loctite instant metal. Several years on, they are still in place.
The tips also are useful for extending the length of the tailpipe of replacement exhaust; some replacement tailpipes are a little short, and the tips extend them so that the end profile is the same as the original following the curve of the bumper.
Depends whether you are fussy about having the original look or not too.