I dont understand why people thing pits are monsters. I have had many pits and many huskies,(used to foster) and in my opinion, the huskies were WAY more aloof and unpredictable than the pits. Hell, ive seen a standard poddle attack my pit, and he didnt even try to fight back. I have a 90 pound silver pit bull named Levi and he is the biggest snuggle bunny I have ever met. But when he was in the pound, no one wanted him because everyone was scared just because of how he looked. You could tell that he was very well-bred, huge muscles and head, cropped ears, (which I actually think is horrible to do to a dog), I heard several people call him "evil" and a "child grabber". But he is the sweetest dog ever, loves kids, and other dogs, and just people in general.
I think you should give a call to your local animal shelter to report that you found a dog, incase someone is looking for him, they wont necessarily make you take him to the pound. And the scars could very easily be chain marks. Ive seen tons of pits have them, because lots of people just chain them up outside and leave them there, I mean, why get a dog if youre not going to pay attention to it. You could get the scars checked, or even just call the vet and describe them. He probably wasnt fought, fighting dogs typically go for the face and front of the legs, when two dogs just happen to get in a little rumble, they usually go for the scruff of the neck.