Pat, Close.... but not quite! The 280 was basically a 272 with a different deck and interior, it was sort-of a further development of the 272 LE and was introduced in 1988, 2 years before PEARSON re-started limited production of some O'DAYs (Pearson-O'DAY production ended in February 1991). I don't think Pearson built any 280s, in fact.... I don't know how many O'DAYs Pearson built at all, other than the above mentioned (8) 290s, a couple of 322s, possibly a couple of 240s, and several Day Sailer IIIs.
The O'DAY 290 was introduced in late 1990 as the first (and I think ONLY) "NEW" O'DAY design introduced by PEARSON. The O'Day 290 was an updated version of the 1986-89 CAL 28 (aka CAL 28-2 to separate her from the earlier. mid-1960's CAL 28 designed by Bill Lapworth) The CAL 28-2 / O'DAY 290 was designed by C. Raymond Hunt Associates and the redesign from CAL 28 to O'DAY 290 was the transom was redesigned to include a molded-in swim step/boarding platform (like on the O'DAY 31 and 35, redesigned versions of the 30 and 34). The interior basically stayed the same on the 290 as it was on the CAL 28.
I have attached the introductory ads for the CAL 28, O'DAY 290, and a drawing of the 280.