Old code that has been maintained (bugfixed), but not messed with too much (i.e. major rewrites or new features) is almost certain to be better than most other code though?
"Bugfixes" doesn't mean the code actually got better, it just means someone attempted to fix a bug. I've seen plenty of people make code worse and more buggy by trying to fix a bug, and also plenty of old "maintained" code that still has tons of bugs because it started from the wrong foundation and everyone kept bolting on fixes around the bad part.
One of frustrating truths about software is that it can be terrible and riddled with bugs but if you just keep patching enough bugs and use it the same way every time it eventually becomes reliable software ... as long as the user never does anything new and no-one pokes the source with a stick.
I much prefer the alternative where it's written in a manner where you can almost prove it's bug free by comprehensively unit testing the parts.
