Yes.
Your tickets (unless they are non-expiring) will have a lifespan of 14 days, but that clock doesn't start ticking until you use them for the first time.
Untouched, unused tickets remaining on room keys from package trips are just as valid in the future as they would have been on the day you checked in - and upgradeable, etc. in the same way as "fresh"/"new" tickets. As long as you haven't used them yet.