As far as I know, they had facilities to make the lenses. Lets not forget that for a long time Kodak lenses were considered the best in the world.
Even the very early Hasselblads came with Kodak lenses! Hasselblad actually dropped Kodak because they were too expensive and opted for the much cheaper Carl Zeiss lenses... that really sounds like an aberration these days but it was like that in the far distant past.
Eventually when German engineering became "acceptable" after the war, Kodak did use lenses from Schneider notably on the Retinette 2A.
But for the rest, I believe it was mostly Kodak all the way in their equipment.
Kodak was a vertically integrated company. They had factories that produced parts, chemicals, films and so on.
