Just remember that the C&R DOES NOT
allow you to "engage in the business." It was solely meant for collectors to enhance their collections.
That's not to say you can't occasionally sell or trade a gun to others, only that you can't be engaged in a business for profit. Furthermore, BATFE takes a very dim view of you ordering things for your buddies. Again: The license is supposed to be for you to "enhance" your personal collection only.
You have to keep a bound book, just like an 01 FFL, and all purchases must be entered into that book. If you sell something it has to be logged out as to whom sold, etc., just like a regular 01 FFL. Also, if you sell something out of your personal collection that was owned prior to being licensed, it has to be entered into your book and subsequently logged out to the purchaser.
Unfortunately, many small 01 FFL dealers are not savvy enough to know about the 50 year rule and assume that a particular gun has to be on ATF's C&R list to be eligible; This can be frustrating at times, and trying to "educate" them is like trying to teach nuclear physics to a chimpanzee.
Also, if you decide to give up your license, you do not need to turn in your records. (For now, at least.)