My experience with "cold" band organs:

1. Assuming the organ was tuned at normal room temperatures, the
reeds will be out of tune with the flue pipes at low temperatures.
This effect is well known for all pipe organs.  Maybe no one will
notice.  It is a band organ, after all.

2. Additionally, the temperature transition itself will permanently
detune some pipes (both flue and reed).  Organ in tune at room
temperature -> organ out of tune at lower temperature -> organ still
out of tune when returned to room temperature.

I assume this has something to do with mechanical tolerances and
thermal expansion excursions: the tuning slides move and reeds get
cranky.  I usually have to retune some flue pipes and clean and
reassemble some reeds.  This is the case with my personal Wurlitzer
145.  Your experience may vary.

Bill Finch