Jungle Carbine markings

[vimydog]

I have a have a Jungle Carbine with these marking on it ,can someone help with information on them?.On the stock is a circle with 506 an arrow under it with 11-55 under it.On the stock near the trigger guard is a crown with the letter F under it. A little back is 5D ?Thanks

 

[teenahlake]

take pics and post