[78-L] Lambert Pink Cylinder Question

[Clifford Bolling]

 I recently brought home a nice library of cylinder records and found a pink one.  It is # 1028 - OVERTURE - MORNING, NOON, & NIGHT.  I recorded it and it sounds pretty good.  The performers are the London Regimental Band with the Queens Hall Orchestra.  Finally figured out it was a 2 minute pink Lambert.  I have never seen a Lambert cylinder before.
The question is - there is no plaster or cardboard inside the celluloid shell, it is just the shell.  Is it supposed to be this way?  Or is there supposed to be something else?
It fit rather snugly on the mandrel and played very well.  
Thanks!  Cliff