Looks like the answer is “Yes, unless they handle guns a lot.”:
We tested whether interacting with a gun increased testosterone levels and later aggressive behavior. Thirty male college students provided a saliva sample (for testosterone assay), interacted with either a gun or a children’s toy for 15 min, and then provided another saliva sample. Next, subjects added as much hot sauce as they wanted to a cup of water they believed another subject would have to drink. Males who interacted with the gun showed significantly greater increases in testosterone and added more hot sauce to the water than did those who interacted with the children’s toy. Moreover, increases in testosterone partially mediated the effects of interacting with the gun on this aggressive behavior.
Source: “Guns, Testosterone, and Aggression: An Experimental Test of a Mediational Hypothesis” from Psychological Science, Volume 17 Issue 7, Pages 568 – 571
According to public opinion, members of shooting organizations (i.e. shooters) are thought to be more aggressive than other groups in society. Also, guns are generally seen as stimuli that elicit aggressive behaviour. The present study examined whether shooters are really more aggressive than non-shooters. Shooters and non-shooters were compared on measures of aggressive behaviour, aggressive fantasies, impulsivity, and main personality dimensions (i.e. neuroticism, psychoticism, and extraversion). The results showed that members of shooting associations were less aggressive and impulsive than non-members, even when controlling for their tendency to present themselves in a more favourable manner. These findings suggest that there is no reason to consider hobby shooters a priori as more aggressive. A possible explanation could be that for shooters, their positively coloured experiences with guns have changed the aggression-eliciting effect that normally occurs when interacting with guns (i.e. the weapons effect). These findings are discussed in light of the cognitive script theory of aggression by Huesmann.
Source: “Do members of shooting associations display higher levels of aggression” from Psychology, Crime & Law, Volume 15, Issue 4 May 2009 , pages 313 – 325
I do wonder how much of the “weapon effect” might be cultural or tied into the fact that the first study used younger men.