The constraints of the a blocking patent are conceptually another thing - perhaps a different thing physically. The answer to that is something the court may opine.
No perhaps at all in this. Here is the Copax lable description:
Glatiramer acetate, the active ingredient of COPAXONE, consists of the acetate salts of synthetic polypeptides, containing four naturally occurring amino acids: L-glutamic acid, L-alanine, L-tyrosine, and L-lysine with an average molar fraction of 0.141, 0.427, 0.095, and 0.338, respectively
That comes out to 4.49:1.48:3.56:1, which is not 6:2:5:1 in my book.
How well this argument works in court is one issue, but it is obviously possible for mC to have the same molar fraction as Copaxone but not the described 6:2:5:1.
[BTW, the 6:2:5:1 relates to copolymer-1 in general, not the improved version. So this might not be a very strong argument if the process of excluding the big chains somewhat shifts these numbers]