Yes, in a previous post for TET 18 90KH0827C, the 18 after the TET has been discussed whether is could be referring to a size 18". On the Hot Serial Number List, it was me who listed the TET 18 90KH0827C as 19" after reading through the discussion, but that may be wrong, and I can adjust accordingly. It is my list, and it is me who documents what ends up on there. If you glance towards the bottom of the List, you'll see that I have asked for the following:
Please send me a Private Message if you would like to add a serial number to this list, or discuss the year currently documented for a frame.
This obviously extends to the size of any of the frames!
https://www.retrobike.co.uk/threads/kona-hot-£300.95403/
The colour for any Hot was a customer's choice, and if you look at the catalogue, you could have "most" of the Dupont Imron selection. The "Custom" braze-ons would have been available from Tom at the time, and we have seen a few of these, which are usually only evident if it is Cable Routing or something obvious - geometry changes were a bit too complex for most rider to customise!
BTW: I have it documented that another high end bike is the actual catalogue bike - but it is a really long story. It would be great if your bike is the actual Catalogue bike - oh and your TET 40 is on the list as:
TET 040 – 19” 1991 Red - Integral Welded Seat Post Clamp, Triangle cut-out Dropout.
I would say though that the Integral Under Bottom Bracket Cable Guide precedes the later plastic Guide on your frame:
View attachment 597673
I will delve deeper looking for the post where I think jez-4-bikes-max has the 90KH0827C frame painted at Argos, as there is a better discussion on there regarding the history of this frame.
Pip