Ya I kind of figured there would be no problem taking one off at a time and yep there are three per side. But just to be on the safe side - the last thing I need is to lose my mast in the yard. I almost lost my boat in the yard last month while I was away on vacation. The genoa broke lose in some hurricane force winds and was threatening to pull the boat over and all those next to me in a very large game of dominoes. The boatyard had to put the haulout machine with the slings on her for a day or two until the winds died down.
As for the chainplates, they really looked like they are just glassed in. There is certainly no bolt going through the hull. However, there maybe bolts going crosswise over the chainplates but are just covered in glass. I guess I will find out soon enough.