Nope, don't be silly. Ibrahim PBUH couldn't be a follower of Islam as Mohammed PBUH would introduce to the world. Of course, that would be absurd as well.

He was حنيف or مسلم in the general sense of the word as in monotheistic and surrendering to God's will. If you forgot Islam the religion for a moment, all Abrahamic religions are called that because they follow his monotheism in one form of the other. That's حنيف and that's مسلم in the general sense; Pure Monotheism.

I know at face value the verse that argues the religion Ibrahim PBUH says مسلم but there are plenty of other verses that shows this differentiation and that's exactly why Muslims, imo, should always say that he was حنيف as well. Because this differentiation could be lost in translation.

Tldr, no, no one claims that.