It looks like this was a thing that was available at some point. Anybody still selling these?
These? Good luck finding one now.
I bought one from Tapco in the U.S. about 28 years ago. They were made in China.
About 12 years ago, you could still find them for $5.95 in the States.
They only work on a stamped trigger group. There is a bridge of metal on the milled groups that would need to be filed off. Or, the safety would need to be filed down on that side.
I wouldn't do either. But filing on an ambi safety is better than bubba'ing a milled trigger group.
This is a pic that seems to show the safety as having been modified (instead of the milled trigger group):
Then there is the issue of how there isn't a cutout on the left side of the stock for a clean sweep of the safety. That's another mod to the stock.
To be honest, they aren't all that great anyways. I can engage the safety fairly easily with my right thumb when I'm shooting.
If they were still cheap, and you had a stamped trigger group (or had one to swap out with a milled group), and didn't mind filing down on your stock, then it would be a worthwhile mod.
I've seen them selling for $70 USD now. They just aren't worth it at that price.
FYI, they were factory installed on the Polytech Hunter SKS. Notice how it also has the cutout for the safety on the left side. It is a bit of a pain to engage without that cutout.
http://chinesesks.weebly.com/polytech-hunter.html