I pulled my caliper a couple of weeks ago to put the wheel back on after installing a tire. Long story short - I didn't torque it properly and it vibrated out somewhere between SLC and Sturgis.

All the HD dealers in my state are out of them and will be at least a week for an order.

If anyone else runs into this, the part number is 4597m
The size is m10 x 1.5 x 30

I picked up a replacement at the local bolt supplier - perfect fit and they didn't even bother to charge me for 2 bolts.

Just a reminder to ask your dealer for fastener sizes - you can get replacements that are higher quality for better prices (especially if they just give them to you ) at your local hardware store.

 

You are lucky. Could've been a bad situation.