Hi and welcome krtsr9c,
You are correct about where the problem is occurring. It's where the slide and barrel lockup on the leading edge of the chamber block of the barrel. Basically, the force of the slide coming back slams into the barrel because sometimes timing or tolerance issues can cause it to have some interference there. Over time, the abuse the slide dishes out can deform the metal of the barrel and form a burr and can potentially effect the performance of the SR9s. However, this is very rare and I have only seen one other forum member shoot his peening SR9 until it locked up. Everyone else is either proactive about having it repaired until fixed, or just take a stone to it and smooth it out and keep shooting it, with no noticeable effect on the gun or it's performance.
As for a proactive approach to prevent peening, I would wait and see. Normally, less than 100 rounds is too early to know if yours will peen or not. Some guns, including mine show a sliver of shiny metal on that leading edge from wear and hundreds of rounds of shooting. It never gets worse than that for most owners. Extreme cases of peening have started early on (150 or less rounds), others see it starting between 250-1000. Once you get into the 750 range of rounds fired, it's normally not going to happen. I think the percentage of peening SR9c's is considerably less than that of previous SR9's. Ruger implemented a new cut into the slide where this problem is occurring to try and stem the numbers of peening SR9's and I think the ones that are still peening after the new design, are extreme cases of bad tolerances.
My advice is to shoot it and if you notice what you might think is excessive wear on that leading edge, document it by taking pictures of it. Hopefully you have a decent camera with a good Macro function on the lens and can get nice clear photos. Document the wear after every 50-100 rounds and if it's getting worse in your comparison photos, call Ruger. If it has stopped getting worse, then, I'd say the slide and barrel have worn in and should be OK for the rest of the time you own the gun.
Josh