No. They don't even have to be in to be verified. If you have transcripts in and the AMCAS all filled out, then you should submit it. Letters can come later.
You can submit before transcripts are in but you wont get in line for verification until your transcripts are received. your letters can be received at any time and if its after they have submitted your app to schools (post-verification) they will just send them when they get them