I was going to say that surely all those pop-rivets cannot be original!

Is this (the remnants of) some sort of ‘handling round’? The nose cone seems to be (nicely) welded aluminium rather than the glass nose you’d expect for the seeker-head?

Could well be a training round, the head I can see rivets there, the glass ones screw on with a very fine thread, though the head isn’t easy to see properly on the photo, I had some sections of training rounds they are hollow with weighted steel ballast, and not very interesting. I also had the real one which is packed with electronics of the very old fashioned variety, and incredibly interesting.