Our (USA) OPS SPECS do not differentiate as to precision or non precision approach capabilities for filing of alternate airports. The only planning requirements are to add 200' to the ceiling of the approach minimums (HAT) and 1/2 SM to the visibility minimums...for alternate airports with two runways; or 400' and 1 SM for alternate airports with only one runway. Once airborne, these higher alternate minimums no longer apply; in other words, once you actually proceed to your alternate, regular minimums apply.