new here, need help with 1917 Mk iii* questions

I have a couple of SMLE rifles:

A No 4 Mk 2 which i bought many years ago.  It was unissued and packed in Cosmoline.  I cleaned it out and it works fine.

A friend many years ago gave me another one which I shot once and put it away in my safe.  I just pulled it out yesterday and gave it a cleaning.  It turns out it is a 1917 SMLE Mk iii*

I found some videos online so I joined here to learn more.  It is missing a couple of screws.  One is in the bottom of the forearm.  There is a recess in the wood which has a small spring but no bolt.  There is also a missing bolt near the rear of the trigger housing.  I think it might be something that the magazine might "hang on".

Would someone please tell me what these parts are called?  And where can I find them?

Thanks!

However there seems to be a missing screw near the front of the trigger guard.  It's not the one which holds it to the rifle.  

I did some looking around online and I think it's a "Type A" trigger guard. I don't know what the purpose of this missing screw is for or what it's called.

  

also I found a diagram of the breakdown of the rifle.  It shows the "inner band assembly".  It looks like there is some sort of bushing or washer  that sits below the inner band and on top of the forend.  Then the spring and screw below that.  It is listed as part #5.

Am I wrong here?  

I have the spring in my rifle.  Should I replace it anyway or just get the screw and washer?

Done. Sorry for the inconvenience its an anti-spam thing & will soon go away.

I'm on here 2~3 times daily so I don't know how the long delays you're experiencing are happening. I remember approving most of these posts within a day, or at worst overnight.