No they are not but it looks like they are stronger than Goku or vegeta they must be at a level of at least God of destruction to guard King of all Zeno.If we talk about Grand Priest he is one of the strongest guys in Dbs world as mentioned by Whis so there is no way that those Guards are stronger than him
In the manga version it was different than the Anime version and in it Whis states that the Grand Priest is the strongest.
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Tho Zeno could be the one who created the Guards, based on the fact that the Future Zeno didn't have them before and received them after he came to the current timeline. From that info we can assume he created them in order to mimic the current Zeno, as he does that always. So it depends how much power did Zeno gave them, if he gives them enough power, then yes they could be stronger than The Grand Priest. The two Guards could also fuse and the two becoming one powerful Warrior.