The Supraphonic and Acrolite shells were/are the same, actually...only the Supras would then get chrome plated (hence, the pitting problems). It seems that this one was a 70's acro that has been polished. I've never seen or heard of this coming out of the factory, but would never put anything past Ludwig. Although, some previous owner may have had this Acro polished. Either way...good for you...looks good like that!