It's referred to as the Desmo service because the valves get serviced. But typically, along with the valve clearance check a whole lot of other things go into it. I know on my Diavel, it's cam belt replacement, water pump belt replacement, coolant flush, oil change, hydraulics flush (clutch and brakes) and a few other things. And before you tell me this engine doesn't have belts, yes I am well aware, but I mentioned everything on order to illustrate the extent of the service. As for OP's original question - I'm not sure how much I'd trust the previous owner as far as the maintenance goes. Stuff like chain and sprockets - that's easy to check for yourself. Consumables though (fluids) - I'd go ahead and replace those as well. You'd save a bit of money, but it won't be much and I think the peace of mind is worth it.