Recently purchased a 1984 O'day 28. The upper chain plate is actually a system (Navtec I think) that attaches through a rod to the structural pan of the boat. The forward lower shrouds don't seem to attach to anything but the deck. Is this correct. There are no chain plates that I can find.
"chain plate" is often used generically for whatever your shrouds attach to... So you do have chain plates... but one is the 'system' you described, and the other is basically a backing plate for the deck attachment.