The 2005 mentioned behind the scientific name is indeed the year it was described. Prior to that, it would may have had an L-number, but it's also possible that it wasn't L-numbered.
Here's is the first page of document describing the fish. It appears as it was a previously undescribed specie.
Panaque Maccus was described in 1993, so it should have been possible for the LFS to correctly identify it, but of course that requires the LFS actually tries...
In the LFS' defence: a lot of species has been exported/imported as "Peckoltia Vittata". Literally anything that was a small Pleco, in brown-ish and striped would probably have been identified as P. Vittata at some point or another...
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Mats