When a Buyer closes on a home, in Colorado, you receive keys to your new home at the closing table, even if there is a post-closing occupancy agreement in place. You own the home.
If you get possession at closing, it is best to get the locks changed, or change out the exterior door locks for your protection. You don't know if the previous owner ever changed locks when they bought, if the neighbors have keys, or relatives still retain keys. IT IS FOR YOUR SAFETY to change out these locks.
Sometimes each door has a different key, so when you change out these locks, you can have all the locks having one key to make it easier!
Keep you and your family safe, and rekey the property before someone finds a leftover key! It will give you peace of mind!