OK spent a bit of time with Uncle Google today. GM p/n 12581810 appears to be for the
oil pan
kit including dipstick, pickup etc, while the pan itself is part no. 12624617.
Further searching on 12624617 turned up the
oil pan below with AC Delco filter PF48 specified in the description.
PAN 12624617
Spoke to Repco and they cross referenced the PF48 with Ryco Z129. Not really keen on Ryco after my sister's SUV dropped its
oil on the freeway due to exploding Ryco filter.
Will see if I can match PF48 with K&N or something reputable.