There's an old saying...If it ain't broke, don't freakin' break it! I couldn't hear anything out of the ordinary. Btw, Welcome to the insanity! Nice FXR.
I will after work today, at the end when I rev a little u can hear the mechanical noise I am hearing, I recorded that a couple weeks ago for the sound of Evo ldle that sounds so good , I will try tonight
When I do go in to cam chest I will upgrade cam lifters adjust pushrods breather gear ,wanted to leave it stock but who am I kidding, I did cams head work , Andrews power pulley on wide glide and love it, so I wanted to stay stock with super glide , but again who am I kidding !
Based on the two videos, I was say that even though there are rivets down on the cam chest cover I think some one replaced the cam and did not have the proper gear. That Idle does not sound stock.... I would definitely start in the cam chest.... Mine had a very minor whine but your's is very pronounced. I wouldn't wait....