When they are bonded pair, they may prefer to bond less with people. But I had a well bonded male and female budgies. The female one used to fly and sit on my shoulder/hand and giving me kisses and male followed the female one. It took months of time though. I realized if budgies are somewhat bonded, if one of them shows interest in you, the other budgie is very likely to mimic its budgie friend and will also bond with you. It somewhat requires more time and patience to bond with them, if they are well bonded to each other already. But don't give up
I suggest you talk to them softly when you have them sitting on your shoulder and turn on some music for them and keep on feeding them from your hand, it is a good start point to bond, b/c it builds trust between you and your budgies.