Rebuilding 07 Accord SE Caliper questions

47,000 miles on these calipers. I have front passenger side caliper apart. The dust boot was torn in several places so I thought I would rebuild them. I usually don't see the boots torn when I change pads.The piston looks fine. The bore that the piston rides in has some of the finish worn off. If you were looking at the caliper mounted the area that has the finish worn off is between 11 oclock and 3 oclock. It is the typical wear I used to see in wheel cylinders. I am guessing that is from 47,000 miles use. It is still smooth. I have watched a couple of you tube videos on how to do this rebuild. I was just asking for a few pointers and making sure the bore with the finish removed is not a problem. I have rebuilt wheel cylinders on many cars over the years.This might be my 1st set of calipers. It seems easier to do than wheel cylinders for bonded brakes. At $7.99 a rebuild kit that is cheap insurance.
I also noticed a lot of rust build up around the spool where the rotors attach to the hub so I am cleaning that off. I just bought this car and the owner lives 9 miles from the ocean so I didn't know if the air had something to do with this. Maybe it affected the torn boots too. I was thinking the torn,cracked boots became this way from heat buildup. Maybe the combination of heat and ocean air. I will report what I see when I take the other side apart. Brakes worked fine when I drove the car home after purchase. I just was looking over the car like I always do to see what condition everything is in at the moment. Any thoughts?