"Tranch Gun" and "Sten Mark II" are bonus tokens with a create picture on the back: can a player choose them like equipment bonus token?

Thanks.

Yes and no, a character can choose the bonus token called "arsenal" or "firepower" or something like that, which allows the character to exchange that token for one of the weapons, characters cannot just pick the tokens (which is silly, so change that as a house rule )

Hope that helps