All the kits were made by H&K originally for the FAL Rifle (metric magazines) but a number were converted with inch magazines and designated L12A1.
The Canadians called the kit:-
1005-21-864-5568 (also 6920-21-864-5568)
ADAPTER, sub-calibre, 7.62 mm, C1A1
The Poms/Aussies/Kiwis called the kit:-
6920-12-147-6954
CONVERSION KIT, 7.62 mm rifle, 0.22 in calibre, L12A1
The Canadian's redesignated a number of components, weather they were actually made in Canadais uncertain they might of just been 'sourced' through Canada, hence the designation change.