HI
The dogs that you showed dont look like they have been fought b/c the ears would be cropped. They do that so when the dogs are fighting they cant grab on to them. Both dogs as far as I can tell have full ears. I noticed you said you live in the philippines so maybe its different there. Also if they are fighting their dogs you might notice treadmills, springpoles used to build endurance and muscle. (these are often used by non fighting dogs also... so not a really good sign) and you might see bait dogs (dogs of different breeds they use to train their dogs to fight).
If they are from a fighting line just how far back in their line were the dogs used for fighting? The ancestors of the pits were used for fighting thats why quite a few pits are DOG aggressive even though their lines have not have been bred for that purpose for many years. Its in their genes.
A true line of the fighting bred dogs were and still are not tolerated if they are human aggressive, b/c the handlers have to go in and seperate the dogs. So they were not kept if they showed signs of human aggressiveness. They might have a higher prey drive but there are alot of fighting dogs that have been rehomed with no problems after being temperment tested. They have become loving household pets.
I would try and find out more info on the kennel to see if they breed and keep the good temperments in their bloodlines.
I am in no way for fighting dogs in fact I think its very cruel. I own one of the goofiest pits.