If you mean the sliding hatch leading to the main cabin, it was made of fiberglass by Hunter.
If you mean the metal/lexan, overhead, hinged hatch, it was probably made by Bomar. They may be available new. Measure all OD/ID lengths & widths and call them.
If you are replacing the hatch because of lexan lens problems, a local glass company can replace the lens. I had two done for around $110.00.