I have a printout of the honda parts fiche. It shows the bolts. The honda part numbers are 90132-mg3-000, or 96400-08050-00. They are #19 on the picture. partsfiche shows them on the picture, but there listing stops at #18.
The other interesting thing I noticed is that the 85 caliper body has a product code of MG3. Looked this up and that says the caliper body is the same as for a 83-84 XR500R. The only part of the 85 350X front brake setup that has a HA5 (350X) product code is the mounting bracket. Looks like for a 85 350Xwhen trying to find the elusive front brake parts, stuff from a XR500R will work if you have the 350X bracket.
The 86 350X front brake is different than the 85, there are lots of HA5 parts, including the caliper body
ATCnut
82 185s - sold
83 200x (hopped up)
84 200x (stock)
84 70 (lost this one to the DMV)
85 70 (soon to have lights, a foot brake, and CDI ignition)
84 200es (parts trike) - sold
85 350X (the best)
85 350X (siezed motor, dream of a poweroll kit someday)
85 250sx (frame was trash, got parted out)
86 250sx (the tractor)
86 250sx (a nicer tractor)
86 250sx (an even nicer tractor)
87 200x (parts trike, its really rough, a dog was chewing on it for a while)
87 250es Big Red (the tank!!)