Hold on!
#1 - - if you mean that you are taking blocks apart to attach different colors ... I STRONGLY advise that you not do that.
Perhaps you will not meet your self-imposed deadline, but you know you bought the fabric, you have invested a lot of work into the quilt as it is so far, and you still won't meet your deadline if you have to unsew, recut, and sew again.
#2 - - It would seem to me that you have done blocks into rows - - are you simply going to unstitch those rows and insert the new colors between your base? That is possibly doable
#3, and probably most importantly - - you are working with fabric that is older than new stuff.
At the most, it is recommended that you only unsew and re-sew no more than three times, and I very much think twice is almost too much with older fabric. If you keep messing with the blocks by un-sewing, re-sewing, you will lose the block in the end.
Put the project away for a week, and I guarantee you that you will find the fabric - - right where you put it when it made good sense to put it there at the time.
Please think long and hard before you start undoing all you have accomplished <wave>