the hatches will have some id on them, in the glass or along the frame. Windows not so easy. Unless you can get them here or from Hunter, most will have to be measured and matched up to what manufacturers make...or custom cut to fit the frames, assuming you can get them out without destroying them. Else they will all be custom.
If you can not find details on the hatch, then measurements of the frame, radius, depth, slope and such will have to be made and then find as close a match as you can. Else you will have to enlarge the hole to the next known size, or patch and fill to the closest size you can find to what you currently have.
On my 42, I had Bomar, which had been bought by Pompanette and they were very helpful in finding out what work best. Even with that, the screw holes were no where close, so I had to fill old ones, and drill new ones.