GB 1d Red Alphabet 4 Help Needed

I believe this stamp is an SG42 1d red alphabet4 but cannot place the "T" using a comparator. Better eyes than mine might see differently but the T does seem to be placed too high to be compared with any of the ones illustrated. One possibility might be that the stamp TL is one of a missing imprimature position stamps so perhaps no illustration of the "high T" is/was available at the time of comparator manufacture...it is an old one.

Does the item have a legible date,

Pagoda

The postmark is 1863.... but I have not been thinking straight. I assumed that as there were two examples of Alphabet 4 "T" in the comparator and that there were two plates used, then these examples must be the ones to go by. In reality, as these letters were engraved by hand, there will be as many variations of "T" as there are stamps on row T of the plates. That means 12 T's on each plate. They still look like alphabet 4 but if I can now get the plating right I can rest easy

For what it's worth, I make it plate 50.
If plate 50, then it is Alph IV.

best,

Larry

A big help really, thanks. The combination of plate 50 identification and alphabet 4 is ideal.
The stamp is on cover but the cover or postmark does nothing for it so I'll remove the stamp for a decent write-up.

My stamp alongside a known Plate 50 Alphabet IV stamp shows mine to be also plate 50 Alphabet IV.
Thanks, Larry, for pointing the way