That is basically the original setup for a 1984-85 DS II or 1985-89 DS III, although whether the mast section is the original or a replacement, don't know..... the blocks (pulleys) might have been used for some previous owner's modified CB control line setup, but who knows? The plywood at the top is NOT stock, must be a previous owner repair and obviously the plywood wa not properly sealed first.
Deck under the bottom of that mast section should have a section of plastic pipe bearing held In place by a piece of plywood glassed to the underside of the cuddy floor (based on how the DS II prior to 1984 was constructed, that is before the mast was changed to truly deck-stepped with the hinge permanently mounted to the top of the cuddy instead of the original setup of being stepped through the cuddy top with the mast step mounted to the cuddy floor. Standard for 1971-81 with option of hinge cut into mast about 1" above cuddy top, that hinge setup became standard for 1982-83.
Here is a picture of a 1984 DS II showing stock setup.