On a personal front, I'm not an originality freak but a plain and simple Armourer and anything that came into our workshops only ever came in because something was wrong with it. We fixed it and it went out repaired to the best we could and functional. If it came into our workshops, as many did, painted in kakhi or camouflaged, the it'd be stripped back and made good. So if I was you, I'd have it degreased and painted with the standard BritishArmy sunkorite paint, oven baked for a few hours, greased and assembled then put back in its chest or into the armoury. That's as original as it gets.
As for the telescope, we never saw many Mk1's after the mid 60's or so but there were still a few in the system on old tired No4's, you just need to remember that a Mk2 telescope won't make the rifle any better or shoot better. It just makes your chance of a HIT a bit better and that's only out at longer ranges. In other words, if it ain't broke, then don't fix it.....