To my knowledge the first AMD-65 was purpose built with the intent of wood "I" grips and plastic coming later. The AKM-63 full length rifle had wood grips and it would reason that wood grips could be a substitute standard replacement on a AMD-65.
The Hungarians were very thrifty when building their various AK rifles over the years and I would not doubt wood grips saw their way into production over the years to fill parts shortages of the plastic grips.
from what I have seen the Hungarians used a system to to tell you what grip and possibly other changes were on the rifle. I have seen new shipping crates of AMD-65/3, AMD-65/5 amd AMD-65/7. The crates of /7s I saw were the wood grips.