Not a doc, far from it, but anecdotally a friend of my wife has had Covid twice. This article discusses the latest thinking on it:
https://www.bbc.co.uk/news/health-52446965
This seems to suggest that there is a strong possibility that the body will build up anti-bodies from first infection but not sure yet. It suggests my wife's friend may have only had covid once, but it was a form of 'long covid', which got worse some weeks later and she thought it was a second infection. But still too early to say it seems.