Just generic micarta comment. The older formulas use resins which turn yellow with age and or exposure to light. Original paper or finest bleached fine weave linen use, especial on "decorative" instead industrial micartas.

That fine weave seems to be inaccessible to industry now, or too expensive.

Resins have improved but only time tell how improved. Can spot winners from past, though as switched from phenolic to epoxy resin in many case and process improved with better control.

If knife dates correct, no reason to doubt mix of older or newer supply as stock sized for certain knife. Also no knowing exposure of knife since made.