Like I said, if he made his mark, rather than signing, then a mark is what you will see on the original. As he signed neatly on another occasion, it is unlikely it is the same man. Which event came first? It is just possible that he learnt to write very late in life, though this would be very unusual.
The Shropshire registrar's department *may* be prepared to issue a copy of their original copy though some local register offices prefer to transcribe the entry. But a quicker (and cheaper) way is to go to Findmypast where the original parish registers are available online.