There is a question with two answers from two different users that have the same time stamp:
Is the time stamp actually accurate to the millisecond?
Yes, millisecond values exist, but are not shown directly on the site
Using Stack Exchange Data Explorer (SEDE), I've written a small query to demonstrate that the millisecond value exists. The 'CreatedDate' field will not show this by default, but by
CONVERT()ing the field and using the '114' datetime style (
hh:mi:ss:mmm) we can see the milliseconds:
Do note that the data displayed on SEDE is only refreshed once a week, so your example answers won't appear until next Monday. We'll have to wait and see what the milliseconds look like. Note however, that based on the Answer IDs in your above links:
Timmy Jim was 'first' :)