The correct Shires Siphon Version for this specific backpack is imho the one with “Made in England” on top of the round section.
It also features a smaller diameter “nipple” on top so the screenused looks different to what most of us have, even though we have original Shires siphons.
I tried to get my hands on one of these for month, even years now...uberrare it seems!
Here is a picture showing this specific siphon...
Note: This is a UP100, so also not completely screenaccurate!