Yes true.
Is trans about internal gender ID?
If a person hasn't told people they have s trans identity. If they haven't changed their appearance. This seems to say they are not trans.
But they are. Gender identity is different to gender presentation.
Many trans people say they always felt that way.
Jenner was trans when they competed surely?
What was not allowed was a very large number of substances that could enhance performance, including testosterone for both sexes.
What was not allowed was competing in the sex category that you weren't.
There was nothing stopping female people with a stereotypically male hairstyle and preference in clothes from competing.
There was nothing to stop male people with a stereotypically female appearance style competing, well in the rules anyway. In practice the old toxic masculinity is a real problem. Men need to sort that out tbh.