Hello again, I posted last week about an SA 03 I have and here is another question. Also in my possession is an RIA serial number 6999. Has a 5/17 barrel with a 2 screw stock marked RI on the tip. I believe the bolt is an early RI because it isn't marked anywhere. There is an additional larger gas hole on the bottom and I was wondering what time frame this would have been done. Thank You.