Guns don't come with "meters" to record shots the way a car records mileage. You get what the seller gives you.
One thing to keep in mind. The seller could have a journal with the exact number of rounds he took to the range each time and whether he brought any back -- it's a good way to keep track of ones ammo inventory. If he took 2 9mm pistols that day, and shot them both evenly (e.g. one 50 rd box each), then he's going to know the round count pretty close to exact.
HOWEVER, dry-fire practice and using a laser training system with that firearm also adds to the round count. Each time he pulls the trigger on an empty chamber, a laser or a "dummy" round, it adds to the round count. Although the non-live round doesn't cause the discharge of a bullet and sudden slide rack, it does require the user to rack the slide between shots. Depending on how gently he lets the slide return to battery, that can cause just as much wear and tear on the firearm as firing it at the range. it could even cause more wear if he uses the laser far more than live training simply due to ammo cost and convenience.
Bottom line -- There's a good chance that everybody who do give a believable round count might be excluding non-live training use. Take all round counts, even "zero", as a low estimate.
To me, the only real use for round count is reliability. The higher, the better. A gun that was never fired could be a factory-induced malfunction just waiting for it's first use.
If you intend to shoot your new purchase, you're going to add to the wear and tear. If you want a collector's piece to sit in the safe, then it's up to you to inspect the weapon for signs it is in new, unfired condition.
Buyer beware.
