I have an 1855 P.T. penny which I bought because it appears to have the date numeral 5s in different fonts with the right hand 5 slightly "fatter".
However, the reverse of this coin appears to have a slightly different design with Britannia's chain mail bodice having what I describe as an ornate central panel. It's a pity that the coin isn't a higher grade but nevertheless it does look different to me.
Normal Plain Trident reverse
My coin's reverse
Sorry about the size difference - it must be to do with the resolution of the originals.