No, they don’t.
Plus you should note that they end in an unvoiced /s/ sound. If they were plurals, they would end in a voiced /z/ sound. If you somehow had one “luca” (whatever that might be) and hence several “lucas”, the latter would end in /z/ not in /s/ the way Lucas does.
Think about Ramses, Hercules, Socrates, Menzies, which really do all end in /z/. Nobody thinks of those as more than one of each of those folks. Similarly, trapeze ends in a voiced /z/, but isn’t perceived as plural either.
Even with nouns ending in -s which are inflectionally invariant between singular and plural — words like series and species — you seldom see confusion in native speakers.
The place where native speakers sometimes stumble with forming their singulars and plurals is when English has wholesale-imported both the singular and plural forms of a classical word from Latin or Greek, and word is expected to still follow the rules of an alien declension. They’ll see words that are already plural like bacteria, errata, criteria, or phenomena, and for lack of a final -s will occasionally misconstrue those as singulars instead and so end up creating “double plurals” like *bacterias, *erratas, *criterias, and *phenomenas. (For the record, the respective singulars are bacterium, erratum, criterion, phenemenon.)
A closely related issue occurs with words like crisis, whose plural is crises. It is not uncommon to see people say crisises for the plural. It’s hard to fault them on that one.