Re: low pitch sax
This is a Martin Stencil. I have one that was my first alto when I started playing 45 years ago and it is still my favorite alto, out of many, today. Mine has a high front F and a forked E flat key that the cup is actually in the front of the horn down by the E flat C pinkey keys that have the rollers, those bow cups.
I have seen them without the front F, but the forked E flat around the front seems to be generic with this design. The Low Pitch A and serial is also generic with them.
Not big value, maybe 650 if it is playing nicely with a newer set of pads. I love them and can always find them under 200 bucks needing some work.