We can't speak for Wedgwood specially, but we have seen pieces by other potters such as J&G Alcock and Davenport where they used both a printed mark with the pattern name and an impressed mark. Not all their pieces have the impressed mark though. We currently have 2 Scinde plates one with an impressed mark the other does not have one. So not everything a potter made will be fully marked and this probably applies to Wedgwood also. Hope this helps and thank you for asking.
Judy and Kim