I do not believe this is a paper phenolic laminate.  I believe that
the material used in both the original and PPCo replacement valve
guides was "vulcanized fiber".  This material is still used to make
"fiber" washers.  A thinner version, gray in color, used for electrical
insulation is commonly known as "fish paper".

The material is less brittle than paper phenolic laminates, and
I believe that it is easier to punch.  Here's a link with more
information: https://en.wikipedia.org/wiki/Vulcanized_fibre 

A little Internet research turned up several sources for vulcanized
fiber sheets including 0.031", 0.047" and 0.062" thicknesses.

Best regards,
John Wolbach