No. The IRS already has your W-2 for both years and, as far as I can see, the W-2's have no relevancy to adding a dependent. You send in Form 1040X and any Forms or Schedules that changed from you original "as filed" income tax return. Off the top of my head I'd think that would be only the Form 1040 itself, but the onus is on you to make that determination.
Tom Young
