It certainly looks that way
I think he primarily works with strikers or forwards who operate in the box or can be considered huge goal threats. Weghorst wouldn't exactly have much of an effect as he is 30 and was only a loan.
Antony always tries to curl the ball from right to the far corner, and he definitely knows how to do that but he just has to be a little bit better at it. I don't think McCarthy could teach him that better than Antony himself. It would be nice if they had sessions where Antony learned to vary his finishing a bit, like how Greenwood did.
Sancho is a really good finisher, but he rarely finds himself in a shooting position and is more of a provider, but also very hesitant and struggles to actually make a decision. He should definitely shoot more.
Garnacho is a big goal threat and I think he works a lot with him. He has had some really nice finishes, but also a bit inconsistent which is to be expected from a player of his age.
Martial.. well, he's just a lost cause, in my opinion. They definitely work together, but his finishing have regressed, but that also happened before Benni came to us.