It looks like the 560 yes, there is a plate inside the transom telling you what it is to confirm.
The searider did set the bar high but they were aimed at very diffent markets. Put it this way, they never stopped making the searider when adventures came out, the clue is in the name really.
Anyways, is it a great rough rib boat.....no. Will it get you home at 20knots in the rough stuff, maybe is the best answer. I only had to come off plane a handful of times with mine as i felt it was hurting the boat and pottered home at displacement speeds, not what a typical rib is all about granted.
It is not a heavy built boat so some suffered from gelcoat crazing along the chines, I've seen a few 560s and never witnessed that but there was a couple of reports of it on the forum. If you go to see one that is antifouled then i would walk away, could hide a multitude.
If it is a decent example check the chines carefully and give them a good push/hit and check for flexing or a hollow sound, If you have any then walk. If it hasn't got any crazing by the ages you are looking at then it probably is pukka though.
The Honda 90 will probably get you in the 32 knot region flat out and will burn about 0.5l per mile if my old mariner 100 was anything to go by, the hull is light and not a deep v so fuel numbers are exceptional. It costs me atleast twice as much to go out on my ribcraft now, horses for courses and all that.
Anyways, hope that helps.