Rescuing ex-breeder pair?

[TheSillyBirbHouse!1!1]

I have recently been considering rescuing a pair of breeder conures, they are turning 3 this year. I’m posting on here because I am struggling to find any advice on the taming and rescuing of birds who come from unideal situations. I’m not sure if they are tame or not, in the image attached to the ad one of the birds seems to be peering at the camera in a friendly way, but I am assuming the worst because of the situation the birds are coming from. I currently own two tiels, both hand fed babies but, I have fostered a cockatiel who was found, abandoned in a house and was completely untame but I managed to make her a good pet, she would step up, get scritches, and even went in my bird backpack. Unfortunately she passed away, I believe for, old age, but she is my inspiration for wanting my next bird to be a rescue. All of that just to say I do have experience with untame birds. So I just want some tips or insight on what I could do for these birds and how they might interact with my flock?