[lugerholsterrepair]

Rylan, Some are some are not. Some original grips I have seen, particularly the Mauser black ones actually smell when rubbed because of the chemicals it was made from. I suspect Germany lacked the exact proper materials at some point during the war and some of the more fragile grips were made with ersatz materials like compressed coal or some other carbon based material.
Wikipedia...
Phenolic sheet is a hard, dense material made by applying heat and pressure to layers of paper or glass cloth impregnated with synthetic resin. These layers of laminations are usually of cellulose paper, cotton fabrics, synthetic yarn fabrics, glass fabrics or unwoven fabrics. When heat and pressure are applied to the layers, a chemical reaction (polymerization) transforms the layers into a high-pressure thermosetting industrial laminated plastic. When rubbed, original Bakelite has a telltale odor.

Bakelite Phenolic is produced in dozens of commercial grades and with various additives to meet diverse mechanical, electrical and thermal requirements. Some common types include:

PAPER REINFORCED PHENOLIC NEMA XX per MIL-I-24768 PBG Normal electrical applications, moderate mechanical strength, continuous operating temperature of 250�°F.
CANVAS REINFORCED PHENOLIC NEMA C per MIL-I-24768 TYPE FBM NEMA CE per MIL-I-24768 TYPE FBG Good mechanical and impact strength with continuous operating temperature of 250�°F.
LINEN REINFORCED PHENOLIC NEMA L per MIL-I-24768 TYPE FBI NEMA LE per MIL-I-24768 TYPE FEI Good mechanical and electrical strength. Recommended for intricate high strength parts. Continuous operating temperature 250�°F.
NYLON REINFORCED PHENOLIC NEMA N-1 per MIL-I-24768 TYPE NPG Superior electrical properties under humid conditions, fungus resistant, continuous operating temperature of 160�°F.