If it's just mud and not rust, maybe much of that could be salvaged, but it looks to me like most of the movement was rusted out. You ain't coming back from that- the "restored" movement looked too pristine to have been just cleaned- the hands and dial looked new as well. Even the patina was gone. Also, looking at some of those replacement parts... I suspect they are not O.E.M.
Replacing parts on a restoration is common, but this video makes it look like they just cleaned off the same ass parts and put the movement back together. I'm calling straight bullshit on that.
Wristwatch revival is one of my favorite youtube channels. Here he is working on a rolex with 1/100th of the rust, and he still has to throw parts out and replace.