Spyderco has, and I believe still does (the website does not mention it but their dealer catlogs show it) factory engraved both stainless and almite knives, in addtion to the "stock" bug and web design you saw they will also do more "personalized" engraving on both handles and blades. Can't say with absolute certainty that the knife you saw is factory engraved, but the chances are pretty high that it is. Have seen a fair number of them offered on eBay by sellers I would trust.
Edited to add: Nice one there Rorschach, most I've seen were engraved on handle only.