Simple answer - No.
It certainly looks authentic, and many of the features do date back to the early 1860's, but as it went through transformations to the Bishop's Palace, and the home of Liverpool University, there were extensive renovations and changes to number 19. In fact it is a miracle so much of the genuine original features remain. A case in point in the fantastic 'raised pattern' wallpaper on the stairs.
It certainly has an authentic age to it, and is over a hundred years old, but all signs at the minute point to it being a 'Lincrusta' linoleum wallpaper, which wasn't introduced to Britain until about 1874, so not original. I'm awaiting a response from Lincrusta to confirm the pattern and dating and will update when I have a definitive response.