Yes, at least at IAD/ORD/SFO the practice is to baord 57s aft of the 1st class cabin. It is also nice if you are in 1st because it makes it easier for the purser to get 1st class drinks pre-flight (and makes for fewer elbow bumps from folks passing by).

But my FAVORITE boarding procedure is on widebodies when there is separate ramp for 1st and C class...

I've alsop been listening in a few times when we've had go-arounds (once at IAD for "traffic still on the runway" and twice at ORD for "possible wind shear") and it ALWAYS makes me feel better to listen in, know what's going on and hear the mechanical calm in the pilot's voice as he calls for the go-round (it always seems to me that the ATCs get more excited about it than the pilots do!)