Most CVPIs will come fleet-keyed. Some privately-issued ones will not.
Be aware that Ford only officially offered six fleet keys, and well over half of vehicles purchased used the first key on the list (1284X). That means if you see another CVPI, you have a pretty good chance of having the same exact key.
CVPIs do not come with PATS (chipped keys); all you need to start the engine is the bare-metal key.
The six key options for the CVPI are 1284X, 1294X, 1435X, 0135X, 0151X, and 0576X. A full set of these keys can be obtained for very cheap. If you are going to a pick-n-pull, it is a good idea to bring a set with you to open doors and trunks. Other fleet Panthers, such as taxis and limos, use the same keys.
It is also wise to consider rekeying your CVPI, if only because the keyway may be simply worn out from years of daily use.
As it turns out, Ford uses the exact same keys for their new PI vehicles plus an 1111X key option. The new PIs also do not have PATS. So if you have a CVPI key, chances are you can still unlock a lot of new PI cars.