I can dig it! I had no idea these even existed until recently. Unfortunately I don’t think they’re all that common anymore. I know I’d like to get my hands one.
They never were common per se'. Some rifles showed up in Canada and were on dealer's shelves for around six months and then they mostly dried up.
There were all sorts of stories about what they were used for or weren't used for.
I've read socalled experts theories ranging from, the stocks were only put on civilian sporting rifles, for export only, to special out of country export to conflict areas, such as Laos, Viet Nam and tropical nations. There are also all sorts of theories about when they started to offer those stocks, starting around 1957 to 1965.
There was some sort of deal made by Century International in the US, early nineties, to purchase some surplus from Viet Nam, supposedly through an oil company that somehow ended up with them. Sounds hokey but that's what I read.
The rifles were not allowed to be imported to the US, because of their Chinese origins, at the time.
The stocks were stripped from them, no ban on stocks and sold separately in the US and other nations, likely for more than Century paid for the complete rifles.
The rest of the rifle was sold off as replacement parts, where they were allowed.
The truth is likely somewhere in between these theories.
I do remember the North Vietnamese did not like the original Chu Wood stocks that came with their Chinese type 56 rifles and wanted something different. It's quite likely that the Chinese came up with the stocks we see on occasion.
I don't believe these stocks were any sort of an attempt to "sporter" the SKS. They're military grade, through and through. Not only that but thousands of those rifles and even more of the stocks came onto the market at one time, along with the SKS M types, which were a real attempt at sporting versions