There’s not good data on anything related to guns and it’s frustrating.
Intuitively it makes sense that if there might be a bear in the woods some people aren’t going to go into the woods because they’re afraid of getting mauled by a bear. It almost certainly has an effect, but quantifying it is going to be hard and subject to bias and the real effect will always be subject to other unrecorded factors (e.g. maybe when they tested one group the bears were hibernating).
I personally don’t think many people who aren’t into gun culture or traumatized by guns give much thought to whether or not someone is going to have a gun in XYZ place … which probably translates to a lot of crimes of passion or desperation (e.g. I need drug money so I’m going to go rob this gas station).