Oh... That thing...
Actually, he mentioned in the video it does require some gun-smithing. The company making it is Addley Precision.
They have a mount for the SVT-40 that has generated... A lot of unhappy customers.
I took a look at the Addley Precision site just now and... Umm... I dunno... I'll let other people spend their money on it and report back, I think. Looks a little too mall ninja for my tastes anyway. It definitely requires drilling and tapping the receiver, and he's asking $129.99 US for it, even though it's a Canadian company.
If you want a good no-smith mount for an SKS, and to support a Canadian company, try out the MagWedge Gen 2 rail.