I'd be very nervous having the boat supported only by the stands. The pressure if supporting the full weight of the hull on those small pads...ouch...I am no marine architect, but I am guessing the hull wasn't designed to take that kind of pressure. I'd hate to see massive dimples on the sides when you launched her!
The boat hull has no problem supporting its keel, in or out of water. OTOH, the yard should be smart enough to know where to place the stands along the hull. Stands should go under bulkheads or other internal support parts and should number about four stands per side for this operation.
When our keel was dropped for a re-bed they supported it with lots of stands. No hull problems at all.