You can see that they were experimenting with limited ammunition because you can see that they mark weapons as "ammunition" aspect. The problem with thieves kits is that there's no place to acquire new ones with gold. That way you could compare the cost versus the expected benefit. When you have to find them, you can't know how common they are without making an inductive argument. And I found they were inconsistently common.
I don't think there was any experimentation going on. I think they probably just took the weapons with the properties that they have in D&D and didn't think too much about what some of them mean.
