I can state that the war reserve refurbishments WEREN'T 'FTR', in fact the refurbishment is sketchy to say the lest (I have two of them) The rifles were full of Australian parts, there are cracks in the top cover and it looks like someone spray painted the metal parts of handguards as you can see the over spray. on the Nylon 66.
FTR has one meaning only Factory Thorough Repair, where the rifle was returned to the factory to be gauged and rebuilt to 'New Standard', this could mean the replacement of bodies, TMH, Barrel Assemblies and anything else that needs replacement to ensure its within 'Factory New' Specs.
There were overhaul programs within the defence forces at Base Workshops, where they would rebuilt the rifles, replacing components and ensuring the rifle meets the standards set down in EMER D118. They could replace barrels and in New Zealand they also replaced Bodies, but at the end of it, the rifles would meet EMER D118 or EMEI D258 (Australian) standards. They weren't marked unless a modification called for it, they just looked very pretty. In the last year of L1A1 use in New Zealand 1 Base Workshops was overhauling 100 rifles a week IIRC
Australian FTR Marking