Thank you. I don't know much about Katy cabooses - actually nothing - but in your first photo I saw something I hadn't noticed before: the cupola appears to be centered on the body. I'm no caboose expert, but I've only ever known ATSF to have extended vision cabooses with centered cupolas.
The other thing that's interesting is that this caboose appears to the short type, like the Athearn, Bachmann, and IHC cabooses. Nearly all the prototypes I'm interested in use the longer kind like the Atlas model, so I've long had a couple Athearn cabooses with no real use for them. The ATSF extended vision is one candidate for a conversion using that model, and it appears that this MKT caboose is another.
Again, thanks for posting it and the follow up with multiple views.