Yep. Holyrood Abbey was established by King David I in 1128.
St. Ninian had established a Catholic Mission in Scotland in about 425 a.d. They've been there ever since.
After John Knox (Presb. founder) in the lat 16th cent. there was no 'Reformation' in regard to clothing. "Priest/Cleric/Clerk/Clark" was worn by all Clergy, regardless of Denomination, the same applied to the Laity. Catholics & the new Protestant groups continued to dress alike. So I reckon, a group can pretty much adopt any Tartan that has meaning for them.