The Prefix for for these connectors, are calling out the color of the housing material.
No prefix (292156-3) = Natural Color
2 Prefix (2-292156-3) = Blue Color
4 Prefix (4-292156-3) = Yellow Color
6 Prefix (6-292156-3) = Black Color
Click here for the Datasheet which shows this information.
So these adapters will fit and function the same, but will have a different housing color.