The centerboard brackets except for the Hunter Edge which I am not sure about are all the same. Foss Foam now New Rudder made the rudders and centerboards.
The 23.5 and 240 (replaced the 23.5) are different in lengths and widths, mast and boom lengths, sail lengths, etc. but not sure about rudder and centerboard which Bob Walker with Foss Foam could confirm if someone would call him for me.
Basically the 26 and 260 are the same with identical rudders, centerboards, masts, booms and sails but the deck is a little different that came in a wheel or tiller configuration.
The hull of the 260 and 270 are the same but the 270 is a wing keel displacing still 5000 just like the 260 thus the masts and booms are the same. You can get an onboard diesel on the 270 only when built or the outboard version. 270 came with the same mast raising system. However it is more difficult to launch/retrieve the 270 from a trailer and of course one ton more to pull
Due to mistakes by z Spar, they left the country but re emerged as US Spars. During that time masts and booms came from two other sources, Dwyer and Charleston Spars. Charleston Spars is tied in with the old Keyon Isomat (parts for Charleston Spar masts can be purchased from Rig Rite unless that has changed at SBO).
Hopes this helps. Also for example under boat info max outboard is noted at 10 hp which would apply to all boats except for the Hunter 27 Edge which the transom design was different as it was a power/sailor. The disel on the 270 was under 10 hp or 10 Hp
I hope this answers a lot of questions