Yeah I would largely agree with this. Geggenpress systems often have a striker that isn't necessary the most prolific. Full backs tend to take over the wide midfielder duty of getting to the byline and wide midfielders, as you say, are inside forwards looking to get into the box and score themselves. It doesn't necessarily mean they are incapable no 9's, there's just more competition in the box looking to score with the two inside forwards and often the full back on the other side in there too. Bobby Firminho at Liverpool would be quite a good example maybe (not looked at any stats but the first player that came to mind) as I don't recall him scoring shit loads but I certainly remember him getting a fair few assists.