Isn't this a GCT Standard tram?

Probably. The question remains how 'standard tram' should be described.

https://www.tramway.co.uk/trams/glasgow-22/

These 'standard' trams received various upgrades during their careers and also underwent a number of changes.

Whether they used different types of trams in Glasgow (after changes) is unknown to me.
A book, with the history of the tram company, would already solve a number of questions. I don't have a book about this and the Wiki page is far from complete.

'Standard' are the trams built in the GCT workshops between 1898 and 1924 to a similar design. I can't find anywhere a different designation being used for these trams which makes me think that even after the various upgrades they were still considered 'Standard' trams. Since we have a tram model 'GCT Standard' on this website I think it's best to designate all trams of the type as such.

Thank you for searching. I will correct it.