Update.
I called CVS and Kim - a very nice lady - went ahead and retrieved my receipts. Those receipts, however, did not have the card number on it; but she said that they have a "gift card department" where they can go and look for the gift card number into their archives. She gave me a reference number and said I would be contacted within a week.
Assuming this is true, I could get the VR numbers I lost and - assuming no-one found them in the garbage and used them - I should be fine. Am I being too optimistic?