You're not wrong but this is a pretty heavy "nature" argument vs. "nurture".
No kid is being raised in isolation of their culture. I'd assume there would be strong correlation to being exposed to movies and TV with people using guns to you gun purchases/affinity.
Children love anything that is remotely a symbol of power in their cultures.
For boys is ofter guns or superheros, for girls is a doll as long as is clear that it represents an alpha female. Girls and boys earn social power by beging linked with "powerful people" and toys simbolize this association.
Guns, swords, chase, hunt are all major staples of boy play. It's primal, gendered, cross cultural and immediately obvious.