Bomar Hatches Changed after the factory fire
At least some of them did, like the one over my V-berth. The outside rough-in dimension Length x Width was okay but the corner radius changed and the new one had a slightly larger radius so the rough-in corners had to be filled in to get a good bedding area for the sealant.
Now, I'm not saying the hinges changed on your model but they well could have.
In any event, the hinges are held on with stainless steel screws and the frame is aluminum, so guess what?

Over time the two parts - the stainless and the aluminum - join and it can become very difficult to impossible to take them apart.
If you get the old screws out and re-use them, or if you get a new hatch, be very sure to use something like Lanocote on the threads.
This afternoon I was working on my forward hatch and took the screws out and they came out really easy after all these years. Nice that things worked out once in a while.