Any item with an ilvl over 40 will automatically be eligible for the maximum amount of sockets. This essentially means that any Elite item will get the maximum amount of sockets it can, except for when a Low Quality Item is upgraded to a Normal item, in which case the ilvl is set at 1 and the maximum number of sockets drops accordingly. In the case of a CV, it would result in a maximum amount of sockets of 3. In all other cases, the maximum it can get is four. When you actually do the socketing quest has no bearing whatsoever on the maximum number of sockets you can gain. A socket quest in Normal will give you the same amount of sockets as in Hell. Same goes for the random sockets cube recipe.
