David, I have copied your post here:

"Glad you posted this Robert, as I haven't completely understood exactly what is and isn't a Crest and Seal. From your
explanation, I take it the difference between #2 and #7 is that one has the lettering actually printed while on the other the
lettering merely shows through the inlay? And is that also the reason the Ziegler's Rendezvous lettered chips discussed a
couple weeks ago here also aren't C&S? Also is there an easy way to tell when a chip has an inlay rather than just a printed
white filled-in circle? "

My answer:
(1) I don't recall the Ziegler's Rendezvous post. Perhaps you could send me a link to the post, or reference.

(2) Your question about #2 and #7 raises the basic issue of the difference between a litho inlay (#2) and what I call a plain one-color inlay (#7)

It is easy to spot the PLAIN (always one-color inlay) inlay chips like #7. I also call them "silhouette" inlays because the image is created by profile or silhouette.
There are always just two colors -- the base color of the chip (here brown) and the color of the inlay (here white; usually the inlay is always white). Now, the inlay is always die cut (the white plastic inlay here is die cut) so the image or letter or letters is seen by the contrast of the brown and the white. Here as you say, the brown clay color peeks through the white "holes" in the inlay, and you see the "PC."

#2 is a LITHO inlay chip. The inlay is always composed of two or more colors (here, white and black). The chip is one color (here, blue). Here there is no silhouette or profile effect. The design or name is simply (usually) printed onto a piece of paper which is then laminated with plastic. That is the inlay.

(3) I am not sure what you mean by "printed white filled in circle." But you can always tell if the chip has an inlay by using an exacto knife and prying up an edge of the "inlay." If you see a recess in the chip, you know you have an inlay and not a paste-on or printing onto the chip. In the latter case (printing directly on the chip), there is nothing to pry up.

Robert