Even DP furniture was out of specification (warped, soaked in oil etc etc) and as one of the most expensive parts had to be checked and certified as unservicable by the Inspectorate of small arms before it could be declared DP
Any furniture that could be made usable was made usable - scrap furniture went to DP rifles.
Things like screws etc that were servicable COULD be used on DP rifles, but not any servicable Furniture, Barrels, Bodies or Bolts (the costly bits)
Instructions to armourers :