No 3 Mk 1* Questions

I have an excellent 1916 Eddystone Pattern 14 that went through the Weedon Repair Factory sometime between WWI and WWII. I have the following questions about this rifle: First, is there any way to identify when the rifle was converted (date)? Second, I assume the green paint on the barrel underneath the wood is to protect the metal from rusting in a high humidity area, so was this done at Weedon or somewhere in theater? Thanks for any information.

Painting was authorised in the old Equipment Regulations for in-theatre Armourers who didn't have access to the usual Browning and later Phosphating facilities.

At a Base Workshops, as Weedon certainly was, it was Browning until replaced by the far better phosphating in, I think, 1944