Flush rivetted tenders came first then the rivetted ones later on

I was looking for but here's a brassmaster's kit of it, pretty sure this variation came with the 4Fs when they were outshopped (Might be wrong on that though) Then came the one we all know and love (somewhat) with a different design to the cab area

Yes it is! As I understand it the Deeley tender came first ofc with another body before the one I've just posted of MR No.1000's tender, next came the Fowler design which was shorter but taller and that was constructed in 1924 but with a different cab area. I cannot for the life of me find the one-

Something similar to this style wasn't seen until this era of mainline steam (in this country), mostly seen on Tangmere