It turned out to be a MR-65B which is stereo It cleaned up nicely with some carnuba wax and elbow grease. It sounds ok but I'm going to have it looked at. The chrome chassis has no rust or pitting and it looks pretty nice.The guy also has a Barzalay cabinet that all his Dad's Mac gear was installed in and I'm trying to get that also. It matches my speakers and my stuff will slide right in and the cabinet matches my Altecs.
His "big" Altecs turned out to be 846B Valencias and they sure cheapened up the cabinets on the B models.
He has a plie of Mac gear that was his Dad's and I'd love to have it but I told him he should keep it and about what it's worth to my understanding.