What is this stuff on a pulley bolt?

[dromano]

After I removed the timing belt I checked all the pulleys for slop or rattle. All were solid but, a lower idler pulley so I pulled it. All the pulleys I removed to get at the oil pump were tight, too tight I think. Here are some pictures of the stuff that came out of the bolt hole wrapped around the bolt threads:

I first thought it was thread lock. It looks like aluminum, it's silver and acts like metal, a baby coil spring with pieces. Is it threads from the hole? I put the pulley back on after I cleaned the bolt, the bolt snugged right up and the pulley did not rattle, it was solid.

Should I use thread lock on the pulley bolts when I put every thing back together?

There is a piece above the oil pump that has what I think are 2 crank sensors, do I need to remove it to get the oil pump out?