I don''t remember GF spec rifles - whatever they were........ We had those marked EY in yellow on a dark green band around the heel of the butt. We also had sub-standard or second standard No1 rifles that were generally in the school Cadet Forces. These sub standard riifles had a silver band around the butt and were perfect, fireable etc etc but had slight barrel or tolerance specs that made them safe to fite but don't ecpect to win any prizes - as said to me as a youngster.
We also had DP No1 rifles that were later designated as DRILL RIFLE L59 A2. I saw a couple of them and kept one but the conversion to L59 DP spec caused no end of trouble due to thee being so many variables, they were impossible to hold in the machining jigs! The DP rifles were always categorised as BR-PC or BR-UF until they were certified as ZUF. Beyond repair, provisionally condemned, Beyond repair unfit to fire and then Z - base workshop or factory repair, Unfit to fire