Redfoot Tortoise Plastron chipping?

[BrandyBacklash]

Hello, I have a redfoot I got about 2 months ago from a lovely couple who couldnt care for him, His name is Paco, I believe he could be about 10 years old. Approx, 7-8 inches long.
He eats well, poops well, soaks and drinks and pees well. He has started coming out and being social with me a few weeks ago.
Just the other day I took notice of these areas on his belly. I dont know if they were there when I got him and I just never noticed, or if they are recent. It appears as if its been chipped at. I have found absolutely no little chipped off pieces anywhere.
SO..What is it? is he okay? Im a worrier by nature and usually blow things out of proportion but I know redfoots are more prone to shell rot so I thought id ask. His shell is otherwise lovely as you can see in the first two photos... =( Help please!!
(the little bits of wetness on him are just water, he had just had a good soak)

 

[Raymo2477]

To me it looks like old shell rot that has healed.

 

[Yvonne G]

That's how it looks to me too.

 

[BrandyBacklash]

That's how it looks to me too.

Well then I am guessing its something he had and I hadnt noticed till now. Like i said he was with an older couple, i believe they only had him for 6 months before they realized they couldnt keep him. Before that he was owned by a petstore. "that fish place, that pet place" in Lancaster, PA. They are actually pretty great with their animals so if it is indeed healed shell rot i can only assume he was brought in by a customer, treated and then sold. Lucky me?
Im hoping you guys are right and no one pops up to say anything different haha