[_Spook_]

I recently updated my LibreELEC-Generic.x86_64-8.0-Milhouse build from build #0416 to #0424 and I used the '.tar' file.

But I just read on https://libreelec.tv/download-temp/ it says New Install and Manual Update for LibreELEC (.img.gz)

So did I use the wrong file to update? it seems to have worked ok.

No, you did it right. You used the automatic update option. The .img file is for clean install or doing a manual upgrade. So you are all good!