Is it possible to create a new model type for an armor. So say for example you could make PMBZL as a new armor model or do I have to replace an existing one?

You can create completely new armors or whatever, but usually you modifiy an existing one to get the size and animations and stuff right. You can save that under a new name of course and use it in the game wherever you wish.
Making new stuff rather than replacing existing stuff is harder, more work and more things can go wrong, but it's also much better for the user and usually better compatible with other mods.

I don't think that anyone has successfully added another column to the appearance.2da file (that the game engine would actually recognize). Most people that try to add a new armour model have to settle for simply replacing existing ones.

hey there Fallen Guardian I try to make a custom armor well I did the armor pretty good but failed in putting it in kotor if anyone can show us how to put it in the game that would be sooooooo great!!!!

Well that stinks. So if that doesn't work I have another question: How come when I get my custom model for the specific character the texture shows up as just a shiny grey instead of what it was supposed to be?

hey fallen guardian you got your custom model in the game???!!! if so how???!!!

I just ended up making it so all the appearance.2da lines of my character were the name of the model and the texture. That way it worked, but I couldn't make it so anyone could wear it.