not knowing that much about R1b .......( even though my mother line is from it )
it has been found in ancient illyrians as per the recent croatian paper
(POP17) is a Copper Age sample that is R1b-L23. The Croatian Copper Age ran approximately from 2900 to 2500 BCE,
and the Daunian sample ORD004 ( daunians are illyrians that went to Italy circa 1000BC )
but the main Illyrian marker for over 2000 years is G2a2 , found also in tyrol, north-italy, austria, slovenia, croatia, bosnia
which sample is your illyrian from croatia ......do you have an ID #