Here are the Source Verses:
First - Yosef identifies himself as "G-d fearing" 42:18
Subsequently, his servant sounds like he recognizes "Elokeichem" 43:23
So we have in place 7 Mitzvot B'nei Noah, but no Mattan Torah yet. Yosef is a G-d fearer and we may reasonable extrapolate that he is no idol worshipper
Yet in 44:5,15 Yosef and his servant PRESUME that Yaakov's sons should KNOW that he is a "m'nacheish" Now how would they know that - if Yosef is a practicing G-d fearer? Furthermore, Yehudah never challenges Yosef over this apparent contradiction.
On the One Hand [OT1H]
Yosef is into Elokim
On the Other Hand [OTOH]
Yosef is a "well-known" m'nacheish...
There may be room for a clever hilluq here, BUT the simple read is that a G-d Fearing Noahide could be a G-d Worshipper and still do Nichush regularly [as opposed to an occasional deviation.]
And the Brothers were presumed to be cool with this. This strongly suggests that a Noahide is permitted to engage in activity that for a Ben Torah would constitute a form of Avodah Zarah [AZ].
BE"H we will follow up upon this same theme during Parshat Vo'Etchanan - namely that the criteria for AZ for a Jew seems stricter than for a non-Jew.