If the sails had been fro ma DS III, they would most likely fit fine on a DS I or II, but some of hte DS III boats came with roller-furling (luff-wire type) jibs and so hte jib would not have hanks. A local sailmaker could add them for you, or I think you could get the hanks from SAIL-RITE KITs on-line and add them yourself.
These sails may also have come from the same sailmaker used by an O'DAY 19 owner who posted on the O'DAY owners about his new sails being too small, and so maybe the wrong logo was put on?
If these sails came from an O'DAY 17 ,and yes there was such a class many years ago, the specs that I have seen for the O'DAY 17 list sail area as "160 sqft" and hte DS (I, II, or III) have 145 sqft of sail area. So, they may be larger than DS sails. Funny thing is, all hte pictures I've have seen of the O'DAY 17 have the Day Sailer logo on the sail...........?
Basically, the O'DAY 17 was configured as Uffa Fox originally designed the Day Sailer, with no cuddy, picture a 1960's Javelin, but built on the Day Sailer hull. George O'DAY added the cuddy to the DS against the wishes of Uffa Fox.

- O'DAY 17a.jpg (144.75 KiB) Viewed 36003 times