I dont know about the SLC's but my 10x42 EL's # is located under the focus wheel. Under meaning it snaps backwards to allow for finer focusing for one eye to compensate for eyes that are not equal but have differant charecteristics. When you slide the wheel back, the # is under the wheel. On my range finder its under the battery. They are masters at hiding serial numbers. Look in any available movable or removable part.