The dug fuze that you show looks more like the Armstrong Bolt percussion fuze on the british fuze list as No 1
Do you have any pictures of the Armstrong Bolt Percussion fuze?
All I could find is a cutaway, which suggests that the internal arrangement on an Armstrong is different than that of the RL Mk.II.
What we have is, internally, definitely the latter, just without the square hole in the top that the British version has.
The way the hole is drawn in the Romanian manual might suggest ours had a round hole intially, but all the ones we've ever found have no hole at all, so it might be that's an error which slipped in when someone dupicated the original Armstrong drawing for the manual and assumed the hole on top must be round, because he's never seen the actual fuze, just the drawing he was copying.
Speaking of which, I assume the only reason to have it is to tighten the fuze down onto the shell and I have no idea how we did it. I mean, there is a small cylindical hole opposite the big one through which the safety wire is inserted so I'm assuming we used a "J" wrench, but I have no definite proof that is the case.
And the fact we have a fuze lacking the hole and a date of 1884 would suggest that is a modification made by Armstrong themselves and not somethign we did later in Romania.