I was checking out an old sax in person yesterday -- a "Chicagoan" alto. Beveled tone holes, which tells me it's a Martin. The alt-F# key on the right hand doesn't have a key pearl, just like Handcrafts...but doesn't have the split bell keys...both on the left side, engraving on the front.
Never heard of this stencil...wish I had a photo to upload. Is this ringing a bell to anyone? I read that Martin handcraft stencils can be valuable...Not sure.