I've received about thirty of these. Here are three. This first one's from Steve Bailey…
Your memory is quite correct regarding the final Henry Blake episode of M*A*S*H. It did indeed end with a montage of Henry moments. I remember that because I was a teenager when the episode first aired, and like millions of Americans, the ending shocked me. After Henry's death was announced, I hung around after the commercial, hoping that they'd come back and say it was a horrible mistake. Instead, the montage came on, and that was it.
And this one's from Peter Cunningham…
You're absolutely right. The scene with Radar in the O.R. was the final scene of the story, airing right before the final commercials. The montage was the tag. And that's how it is presented on the DVDs which restore the original network broadcast. Anytime the O.R. scene is the tag, that's an edited syndicated cut.
While this one's from Mary Lou Wallace…
You are remembering the tag correctly. I audio-taped the episode and listened to it so much that I have it committed to memory to this day (I do have all the episodes on DVD). I no longer have the tape but I will swear on a stack of TV Guides that you are right!
Okay, so unless someone comes up with solid proof to the contrary, I'm figuring that's how it was. Meanwhile, Matthew O'Hara points me to this article which proves that Henry Blake's death was revealed to the general public before the show aired. Guess that's how I knew about it in advance.