There is no blue circle "era". That's an import cue, Kao Kao out of Taiwan iirc. You could by them on fleabay for around 60bux. The last US-built Palmers(iirc some of these were made by ADAM) were sometime in mid-'90's. These asian versions started showing up in '96-'97. There was a Triangle logo and the blue circle. Not bad cues but they're nothing like the Palmer Originals.. http://forums.azbilliards.com/showthread.php?t=190377&page=3
Yes- that blue circle is NOT considered a true Palmer cue by any collectors that i know of - it is just a knock-off! The last true palmer custom cues still had decent build qualities and playability.