Mal, thanks for the explanation. I guess I can see your point, though somehow I still can't picture enough people wanting to edit their posts to have it be a problem. But who knows, maybe it would turn into a free-for-all.
Probably what I'll do is wait until I've accumulated quite a number of new data entries, then copy the original post and make the desired changes to the serial number list. Then I'll ask a moderator to replace the entire initial post with the updated one. I just don't want to be a pain in the neck by pestering the mods every couple of weeks or months as I uncover new information.