Serial numbers

I am very leary of purchasing anything off of the Internet, but almost of the people I have dealt with online have been very honest and I haven't been burned--yet. One thing I was curious about was whether knowing the serial number of a VX2000 (or anything, for that matter) would be important. Some of the online auction vendors who have sterling feedbacks are selling camcorders for a little less than the big boys, like B&H. (Yes, I know that if something is too good to be true it probably is.) Anyway, has the VX2000 changed any at all (revisions, firmware, lens, etc.) since Sony released a few years ago? I don't want to shell out $2500 for a unit that is one of the first ones produced. Thank you for your time.