Updating assets from the asset store: do I have to also reimport them?

Sorry if it sounds like a silly question, it is. I just opened Unity (5) after a while and I updated a few assets I had bought. However, it says “100%” and nothing happens. That leads to me thinking that it has re-downloaded the .unitypackage file but the asset has actually not been updated in my project. Is my assumption correct?
So, should I also re-import it every time?

Downloading it simply puts the .unitypackage on your machine. You will have to re-import to update your projects.

Thank you, I was also wondering this, I had been updating an asset then clicking import to re-import / upgrade the asset in my project but was unsure if this was the correct way of doing this, so your answer has helped me.