I think you'll find it depends on how much they took away in the beginning. I guess you can have your breasts removed (I've had breast reduction surgery and it's quite painful but perfectly possible), and of course they'd stop feeding you tons of testosterone, but as for the rest of your surgery - well if you'd had a hystorectomy in the beginning they can't replace that, can they?
But it is completely theorectical - because I doubt anyone would do it for you. To get your first sex change you'd have a long, long process to go through, and I doubt you'd be welcomed if you went back 10 years later and asked for a reversal!