Judging by the Bruce Y-DNA Project, it appears that King Robert the Bruce could have belonged to R1b-S7432, which is right below DF27>ZZ12>ZZ41:
https://www.familytreedna.com/public...frame=yresults
https://www.familytreedna.com/groups/bruce/about/goals
http://www.ytree.net/DisplayTree.php...032&star=false