As with the original horcrux spell, I would only be able to enter a victim who contacted the physical horcrux... and I had hidden my unnumbered horcruxes in places where nobody would ever find them.

"My remaining hope was the horcruxes I had hidden in the hopeless idiocy of my youth. Imbuing them into ancient lockets, instead of anonymous pebbles; guarding them beneath wells of poison in the center of a lake of Inferi, instead of portkeying them into the sea. If someone found one of those, and penetrated their ridiculous protections... but that seemed like a distant hope.

The text suggests that Riddle was stupider at a younger age, which is when he made v1 horcruxes, and used story-like hidding places like those mentioned above. Then later on when he was porbably at least 'twice [harry's] age' he grew wizer, made the horcrux v2, and started hiding them well. Then he dies, and finds out that his only hope is the horcruxes from his youth, which weren't hidden well, and it is suggested that Quirrel found one of those, so likely a v1 horcrux.

At any rate, even if we just focus on the 'one of my earliest horcruxes' part, that still heavily implies a v1 horcrux.