and is there a requirement that you ACTUALLY HAVE curios and relics that you've collected, or simply that you might in the future?
A C&R license only pertains to future purchases. It allows you to purchase any rifle or pistol that is classified as a C&R, without going through an FFL. With the C&R you must keep a log book of any purchases where you used your license to purchase the firearm, and any dispositions of these firearms. No previous purchases or non-C&R firearms are logged. There are no minimum or maximum requirements for use, but since it is not a business license, you have to watch how many that you sell.
If you can legally buy a gun, than you can obtain a C&R license.