I have several O'DAY 22 Brochures, I've pasted the Safety part of the Standard equipment list for 1978. I checked my other brochures, 1972, 1973, 1974, 1976, 1977, 1978, 1979, 1980, and 1981 all list "Positive foam Flotation" as a standard feature. Interesting, 1981 lists it as only being under the V-Berth, I guess if one of those models swamped she would float bow up?
Personally, I have mixed feelings about flotation on a cruising boat like an O'DAY 22, nice to know that if she sprung a leak, she won't sink out from under me....... but, how much stowage is lost to flotation? Probably not enough to really matter (under cockpit foot well is not overly useful stowage anyway, would like to have some stowage under V-Berth, but if foam doesn't take up all the volume there, some items can still be stowed if access available.