All Classics and most SEs self-discharge. I've heard earlier SEs (I'm guessing pre-1988 models) may not and I know all Pluses and earlier don't.

My approach:

SE/Classic: Work immediately. I've worked on scores of these, including messing with CRTs, and have never had an issue.

Earlier Macs: Keep it unplugged for a week, then work.

The reason you see the instruction to use a discharge tool in old manuals is for liability sake.