John H Turner, if you look at the underside of your sight what number is stamped on the main parts? Mine is numbered '18' It came from the UK a number of years ago, I managed to get it off of that wonderful auction site.
Here's the rare Australian NRA Target Rifle. There is no magazine well and the majority of machining operations to the receiver weren't done, it a huge lump of steel a lot stronger than the L1A1 Body. The problem with them was they were a straight pull rifle and when up against the conventional Omark Target rifles it lost out. About 130 rifles were made in both left and right handed versions. https://www.milsurps.com/images/impo...8dsedqad-1.jpg
I owned one for a while...it's now either in a gov't reference collection, or been smelted...