It the two birds are bonded with each other then it will decrease the likelihood of them bonding strongly with you. They will be happier as a pair however so its definitely better for them. This does not mean that you cant tame them however. It is easiest to do this when they are young. I would allow them to settle in for a week or so, and during this time talk to them soothingly and quietly whenever you are near by.

Next I would place your hand in their cage in an unthreatening manner (do not try to pick them up at this stage or make any sharp or sudden movements). Then gradually progress to placing your finger gently up against his breast/legs in the same position as his perch and eventually he should be comfortable stepping onto your finger and allowing you to handle him. You need to talk and handle them a couple of times a week to keep them tame.