It doesn't have/need an L number, it's a described species, Parancistrus aurantiacus. And 30cm/12" is probably about their maximum size. L056 is a Pseudancistrus.
I got 4 of them from Snookn21 but lost one in the quarantine tank when some cardinal tetras got ick. Have just started playing with temp and water conditions in a couple tanks to see if I can bring out more yellow.