Check with Catalina for particulars on your boat. They have always been helpful with questions that I have about my Cat 38.
We all tend to recommend or return to equipment that we have experience with. That said, I have had very good luck with the good old Martek Elliptical folding prop. We had one on our 30' racer cruiser and it served us well enough that I ordered one for my (new to me) Catalina 38. I gave model and year of the boat to the manufacturer and they sent a prop that is perfectly matched to the boat. It works much better than the fixed 2-blade prop that we had. There is less prop walk in reverse and reverse is very positive. Plus we get almost 2 kts better speed in forward. Do your homework, close your eyes, hold your nose, and dive in !!! You should be happy with whatever folding prop you get!