For OP's intents and purposes it is likely immaterial but...
Here is how to distinguish close-looking multipunctatus and grandiops. Also, my understanding is grandiops is by far and large more prevalent in the hobby, like 100 to 1 (?).
PCF:
http://www.planetcatfish.com/common/species.php?species_id=710
General Remarks S. grandiops and
S. multipunctatus are most reliably separated by pectoral-fin ray counts with
S. grandiops having 1 pectoral fin spine with 7 soft rays and
S. mutipunctatus having a count of 1, 8 . The soft pectoral-fin elements (i.e. the rays) are almost always branched (the only exception being the last one or two rays, which are sometimes unbranched) a ray is counted as one at its base before it branches out. Also keep in mind the larger adult size of
S. multipunctatus.