A couple of things. Patrick is correct in that a Scotch Deer Stalker would be a drink, however that is how they were marketed--I have seen the original catalogues with that listed.
Second, I have heard some accounts which are not substantiated of Mk II** being used at the front. Given that they had even tighter chambers than the Mk III I suspect they would have been a pain in the *** with crappy British ammunition. I have a few Ross myself (II** and 5*) that have CEF stamps, suggesting that some at least of the first contingent went to Englandwith the troops, but apparently all were issued with Mk III before going to France
. However, could some of those earlier Mk II rifles gone to the trenches? Maybe, but not officially, that is for sure.
The early Mk II** target rifles had a two piece topwood with a barrel mounted sight in addition to a bridge with the target aperture rearsight of some sort. The later ones had a one piece topwood with no provision for a barrel mounted sight. Is that what you are referring to? You have a bridge with a BSA Martin sight and a front sight. I assume the front sight has a hood on it. Further to tiriaq's question, this rifle has a commercial serial number on the left hand side just in the front of the receiver, above the stock? If so , it is a commercial target. The military issue ones had the usual military type serial on the right hand side of the stock and no serial on the metal.
Personally, I would NOT drill and tap it if it is original aside from having the stock shortened. That can be changed, or if you find one with a good stock and bad metal a good complete rifle can be made. Once this is drilled and tapped, it is screwed forever.
Ed