poppop

While replacing my tires last week on my 2017 FJ-09 I found the two lower front brake attaching caliper bolts had a great deal of corrosion and rust.  The bolts for the upper attaching points were like new.  Have new bolts ordered but of course they are not in stock and won't get them till next month!  Has anyone else seen this problem?  When I put new tires on last year all 4 bolts looked like new.  Any idea(s) what the cause could be?

Has any one tried the Conti Road Attack 3 tires on your FJ?  I've heard they are great in dry and wet conditions and warm up quickly. Not thrilled with the stock Dunlops.  They only have 2500 miles on them but seriously considering changing soon.  Would appreciate any feedback you can provide.