Hi - I have a 1979 Hunter 27 with a Kenyon mast. Where you put the slides in the internal track for the mainsail, there is a cover or something that is missing that would prevend the slides from falling back out when lowered. I imagine that this was something that would swing out of the way to put the slides in, but would be helpful in keeping them in at other times. There is a screw hole there, but no plate or anything. Thanks.