I thought that the original bill of rights could not be altered in any way, including by the amendment process?
I believe the Constitution only had two "unamendable" sections, one of which is no longer in effect.
Article V: Provided that no Amendment which may be made prior to the Year One thousand eight hundred and eight shall in any Manner affect the first and fourth Clauses in the Ninth Section of the first Article; and that no State, without its Consent, shall be deprived of its equal Suffrage in the Senate.
The first of these referenced prohibiting the slave trade prior to 1808, when such prohibition was passed, so no longer applies.
The second is still in effect.
Personally I find it difficult to see how an amendment, which can completely change the Constitution itself, can be prohibited from changing this provision. But since nobody is proposing any change to this single provision, it doesn't seem to make a difference, as Hilary might say.