Good question - I was going to correct someone earlier in the thread and I then realized I didn't know the answer to that one myself

I would say there's certainly no harm in using the current pronouns

I believe the most respectful usage would be: "Caitlyn Jenner won her gold medal in the Men’s Decathlon at the 1976 Olympics." That is both the current name and pronouns are used to refer to past events.

Side note: someone who goes by she/her pronouns could enter the Men's Decathlon as they don't use pronouns to determine eligibility.

The most respectful is #3 and my view is from being transgender myself with knowledge of what others similar like me would desire as respect. Similar problems happen when a transgender person is murdered and the authority finds it by arguable belief that it’s necessary to report the birth sex for trying to catch the murder. One of the reasons I hope assisted suicide becomes legal for anyone.

Using the current name and pronouns is correct. If required, you could use "nee Bruce", but it's considered pretty rude unless that person has given the Ok.

So, sentence three is the most polite, but depending on the subject of the article, you may need to offer context at the top or in a footnote.

“Caitlyn Jenner, then known as Bruce, won her gold medal in the Men’s Decathlon at the 1976 Olympics.”