D&R Marine should have that original locking tab for the cuddy door panels. It is a sort-of "L" shaped stainless Steel part that has 2 holes in the short leg that bolt to the aft bulkhead of the cuddy and a larger hole in the long leg that allows fitting a padlock or pin to hold the boards in place. I could snap a picture of mine, but my boat is 45 miles from where I am right now and it will be a couple of weeks or more before I next check on her.
D&R Marine (508) 644-3001
www.drmarine.comI don't think Rudy has that part on his web site, but if you call he will know what you need.
Or you could make one, I have often thought about replacing mine with one that could swing out of the way into the cuddy when not in use (Gave myself a nasty head wound one time when I tried to crawl into the cuddy to work on something and caught that locking tab with the top of my head, OUCH!! Kind of bloody too! I now slip a rubber cover over it after opening the cuddy.