This is clearly a pressure model as it has an air-tight cover to the
spool box.

I agree the stop listing is the same as a model "S" (I had one of these
for 10 years), but that model is a suction machine.  I believe yours is
a model "M," which until now was known to me only in Australia.

There are at least twenty-seven models of the 58-note Aeolian Reed
organ.  Please contact me privately with further questions.

Sincerely,
Kevin McElhone
Northampton, UK