Did Naruto stack Sage Mode with Sage of Six Path Mode? Naruto received Sage of Six Path Mode from Hagaromo. At this moment, what was Naruto "final form"?  


KCM + Sage Mode(Toad) + Sage of Six Path Mode?  
KCM + Sage of Six Path Mode?  


If it's the latter, did his Sage Mode(Toad) transformed into Sage of Six Path Mode? Is there any other explanation?
Naruto had already unlocked KCM+Sage Mode before getting extra powers from Hagoromo(when he was fighting Sage-Obito alongside Minato)

Sage of six paths chakra gave him truth seeker orbs,along with a small piece of each tailed beast.

Hope that answers your question.