I don’t mean in a factual manner, correcting or adding information, I mean basically a PR article/brief autobiography. Such as Johnny Vegas’s entry.
I can read about that “portly figure” in his voice no problemo. Aside from some corporate entries I don’t think I’ve ever seen a Wiki entry where the author was so obvious.
Tennis ‘star’ Alexandra Stevenson.
If you click on the “View History” tab, you’ll see quite a few contributors.
Moved Cafe Society --> MPSIMS.
Here’s Jack Klugman’s page from a week before he died. Pretty clearly he did a lot of it himself. But that’s cool by me.
I am awed by your amazing psychic ability to divine authorship.
You talkin’ to* me!?*
I’m prepared to defend my claim, unless you were specifically talking to someone else.
I usually assume that people who have siblings named (like Johnny Vegas) have their pages updated by their siblings, or other relatives (aunts, uncles, etc).
My brother is the one of us more likely to have a Wikipedia page, while I would be the one most likely tasked to update it and keep it clean 
To the OP really, and to blue infinity, as I didn’t see your post (made just a minute before mine), and so did not have the chance look at Jack Klugman’s page. However, in general, I doubt anyone’s ability to tell this with any degree of reliability just from the content. Many of these pages are probably made principally by fans, who will know a lot of trivia about the subject and be inclined to give them a very favorable write-up.
But if you have specific evidence, by all means tell us. I am not impressed by that offered by the OP, however.
A good friend of mine is a published, award-winning writer with a weekly column in a national paper. She had a wikipedia page that she absolutely did not write herself. For what seemed like no reason at all some wiki-wanker decided she wrote it herself for self-promotion and deleted the page! I just checked, she still doesn’t have a wiki entry.
It does make you wonder how anyone thinks they can determine who wrote it. It didn’t even seem remotely like self promotion. It was a stub that mentioned her published work and awards, nothing else.
If a Wiki moderator thinks you’re not famous enough to have a page, that is usually all it will take to get it deleted.
That would explain why mine keeps being deleted. Oh, well, the 3,402,741st time may be the charm.
Well, I don’t know how impressive this is - if the threshold is preponderance of the evidence, I say it was Jack Klugman.
Here are the comparisons between two pages after several edits all made from the same IP.
Besides the very personal
which almost seems like an assurance from Jack to his fans that he’s doing OK, thanks for asking, there are weird little edits, like changing years active from 1950-present to 1948-present, without citation.
This earlier version has lots of weird, uncited trivia that strikes me as the kind of thing an old storyteller would tell anyone willing to listen.
Noting that wikipedia is public domain, I quote freely (and add emphasis):
I mean, there’s knowing about Jack, and then there’s, “come on Jack, stop pretending.” None of those weird little asides have citations, either. A rabid fan would have read this crap somewhere.
I don’t see any problem with a celebrity correcting their factual information at wikipedia. Who better knows their life and career than the person that lived it? Does Wikipedia have a way that celebrities can submit factual information? The cite coming directly from that person as a verified source? That would make the entry’s much more reliable.
It would be pretty narcissistic to correct personal observations. He was a jerk. Hated kids. Kicked his dog. * No, no I wasn’t like that at all.* 
I was tempted to start a Wikipedia page for a friend of mine, who is a successful actor and comedian, but wasn’t sure if it was fair of me to do so. Especially as I would likely just ask him a bunch of questions to fill in all the blanks.
Like ZipperJJ, my brother also should probably have a Wikipedia page, and if he did I’d likely spend some time fleshing it out and correcting errors.
I once fixed my bosses Wikipedia page. Just added some biographical information, like DOB, education etc.
PM me the names and I’ll get the ball rolling. You can fill in edits and make corrections after that.
I think it’s against the rules, although I admit that it’s a little weird. If Albert Einstein were still alive, he couldn’t correct the page on his theory of special relativity without someone asking for citations for every change. I believe there are other user-edited encyclopedias that allow vetted experts to write and edit articles without needing to cite everything.
The relevant guidelines are at Wikipedia:Autobiography. The short version is: