There are two presses of Chuck Flamingo (with black vinyl). I know this because I owned both at the same time. One press plays a lot clearer (and a bit louder)than the other. I only have the loud/clear playing copy now, but from memory I seem to remember you could do a visual check & be able to see a difference. I think the dead wax on the "No one to call my own" side was a lot narrower on the low volume (muffled) press.
You didn't notice the sound difference so much at home, but when we played them out on a big system, it really stood out.
Any one else noticed this ?