The Pre-heresy BA do indeed seem to have used the 'standard' Codex markings, at least to an extent... there are examples of the current Tactical and Assault markings in Collected Visions
, and the coloured helmet system does not seem to have been in use either (although gold helmets for veterans still seem to have been used, at least occasionally). You can find a more detailed summary here
. In general I would probably use 'standard' codex markings for Assault, Tactical and Veteran squads, with Veterans using gold helmets and blood drop insignia.