By comparing the inside bases of the PF61E to the ST3614 (other thread) with combo valve, the latter has an extra inner set of holes. Also, looking closely at the black nitrile material would help determine if the app uses a the combo valve design. The combo valve having an extra circular concave area aligned with the extra holes in the base. Where this thread came to a question was the statement that this PF61E has a bypass, but as typical of GM, it doesn't.
As for the endcap material, it seems more like a felt-like material than Honeywell fiber. IIRC, Champ used to use another name for the material on it's website. Now all it says is "thermally bonded non-metallic end caps."