There is a change for a cross OS malware but it’s probably still quite small.
I would just remove them, and then if they dont re-appear after checking game file consistency then its’s mostly likely not a false positive.
But if you know that last playerd is most likely before you installed current OS then it should be clean. I would check user level autostart and cronjob (so mostly stuff in $HOME/.config) places if something didnt get added, go ahead with life.
Unless you are doing banking and other critical stuff on this machine then I would be thinking of hardedning the OS in some way and/or reinstalling.