The CB on a 25 is hinged and pivots as it is raised and lowered, sort-of like a jacknife opening and closing.
The 1975 and some 1976 models used that winch on a post in the cabin, a carryover from the old O'DAY 23, although the 23 had a fiberglass CB inside a cast-iron keel and the 25 has always had a fiberglass CB inside a molded fiberglass keel.
You might be able to reconfigure a 1975 25 CB to the newer setup, but in the long run, unless that 1975 model is a GREAT buy, it may be better to shop for a newer model instead of converting the older version. The owners who have boats with that post and winch setup find that it works quite well, and in fact if the CB should jamb.... it is a lot easier to stick a stick down that pipe to unstuck it than to try to figure out how to unstick the CB on a newer boat.
One of the few disadvantages of the post is that it may get in the way when the table is folded up while not in use?