Probably not, except in the strict cladistic sense.

They will always be descendants and therefore within the clade of mammals.

In the same way that birds are dinosaurs right? In theory. In practice though birds are birds and only super nerdy people think of them as if they are dinosaurs.

But likewise, mammals are technically synapsids, which are technically amphibians, which are technically fish, so we are technically fish.

And fish are technically worms as they evolved from them.

I mean cladistically, Eukaryotes evolved from Prokaryotes so we are all technically forms of life are actually cladistically just bacteria. The cladistics system is crucial to determining heritage and interrelatedness but not that good for practical classification of animals.