Would anyone buy a gun book with the serial numbers X'd out? If you are truly interested in collecting it is a give and take thing. Provide your serial number to receive information, and your serial number may have additional information that adds to the overall history. Especially on the military pistols, you never know when someone has information with your serial number listed. Also, has anyone ever heard of someone losing a gun by someone harvesting a serial number and claiming it?
I would be much more concerned about writing checks with virtually all your personal information on them down to where you live, and now everyone from an insurance salesman to the cable guy has to have your social security number.