I saw a reso chamber tenor mouthpiece with no stamping on the shank or serial number. It's not like the lettering is gone, it is as if there was nothing there at all. I can't seem to find any info about otto link making a mouth piece with nothing on the shank. Anyone heard of this or seen this before? I didn't know if I should purchase it or not. I saw it at an antique store while visiting my family this past week. I have a few reso chambers, but they all have serial numbers.