While I like the thought of buying the gun that I'm making a holster for, since I'm only a hobbyist, it's not the most practical. Budget willing, I'll do it though :-) In my case, I'm extremely slow in my production, and have had a friend's pistol for a number of weeks now- so, if I were to be able to make a dummy for a reasonable cost and time investment, I wouldn't have to hold someone's gun very long and I'd have the dummy for future use. That's just me though. I don't have a shop or even a dedicated work area, and I work a lot- plus I procrastinate.
Also, I would prefer an accurate dummy over wet forming using the real firearm.
Nooj