What? Is this like Maxwell Smart's "Would you believe...?"

There's an unofficial hull number list on the forum and you might like to look at these entries:
- Code: Select all
1958 O'Day DS I # 307 "Security Risk" swiftsail Santa Rosa, CA
1959 O'Day DS I # 316 "Vieja" dssec Fresno, CA
If #211 is in fact the correct DaySailer class number for your boat, then it would have to date to 1958 or earlier.
Those early years had the grooves in the deck molding giving the appearance of actual deck planking.
However, I'm not certain when this feature disappeared. Also, your version with the L bracket for the CB instead of the thwarts represents a transitional design: possibly (I'm guessing) one that immediately follows the change away from wooden seats and before wooden thwarts were re-introduced.
Now, from another list, we have class # 318 as listed with wooden seats and thwarts. Therefore, my question for you whether #211 is the correct one for your boat. If your evidence is solely a sail number (on the mainsail) that could be unreliable because of people selling used sails.
It would be interesting to have your boat in both databases, but only if we can be sure about where to place it. Otherwise, the combination of features is intriguing, but without means of placing it into the timeline it might confuse the data.