Were the leaves always curled? I might say calcium deficiency, as I have seen similar leaf formation in calcium deficient plants. I don't think the lights would cause that. In terms of the brown spots on the cotelydon, could very well be sun/light damage, especially if they have never been under HPS before. They should be fine, as they will produce new leaves better adjusted to the light strength. If you are worried you could raise the light a little.