The Ballester-Molina grips mount with two screws each that go directly into tapped holes in the frame, rather than the US government standard specs for a 0.250-inch diameter mounting stud and a 0.150-inch threaded screw that fits into the post.
Never heard of a rigaud, but the Sistema- what I referred to (in that link) as "my little Argentine pony" - is a Colt, for all intents and purposes. Colt went to Argentina, built a factory, filled it with GEN-U-INE Colt machinery, operated by GEN-U-INE Colt employees. Then they packed up and left, and the Argentines took over, in that same Colt factory, on that same Colt machinery, and probably run by the same Colt employees.
You know, I see people talk about their Remmy or their Mossy or their shotty or their Springer or their Norc or their Deagle, ad nauseam, and I wonder, "What is wrong with these people, that they have to have their little "baby talk" pet names for their guns.
But then, I've got half a dozen Huskies, and I've got that Ballerina Molester, and I've got several shootguns.