Also if it wasn't clear from the previous posts, I have read (and can't remember where) that certain rifles could have ended up with a mixture of plastic and wood furniture for a time - if, say, there was a wood handguard issue with a rifle around the time of switch over to plastic, the handguard may have been swopped out for plastic, but not the rest of the furniture at that time, so some rifles ended up with a mix of wood and plastic.

Peter or others may be able to confirm if this was correct.