Hi Steve, I got rid of the black plastic jam cleats when I first got my M15. Reasons: When I want to release the jib sheet, I want to do it NOW, and not have to apply equal but opposite pull oin the jib sheet to release it. With a cam cleat, you can jerk the sheet out of the cam cleat and the sheet is instantly free. By all means replace the jam cleats with cam cleats. With cam cleats, life is simpler and definitely far more certain in an emergency. Connie