How to check which model of freeze proof outdoor tap I have?

I am not sure where to post this question, but this seems like a right spot at a first glance.

I have a freeze proof outdoor tap from schell, for which I need to buy a spare part. The issue is, I am not sure which model it is exactly, as contractor who installed it for me years ago is out of business.

As from what I understand it is either "Schell Polar II", or "Schell Polar II Set". There is slight differences between parts of those 2 types, so not sure which one to get.

As upon reading documentation of either, it is unclear how can I check from my end which type I have. Does anyone know how can I check which type of Schell Polar II outdoor tap I have?