Lucas pathfinder

I have just got a pathfinder spot light which has the top lug missing that retains the lamp glass, the one that has Lucas stamped on it. I have got an old lug but it looks like the way it's fastened to the lamp the rivets are cast into the lug. similar to a legshield badge. Any idea how I can fasten it back on, as a last resort I could drill through and use countersunk screws.