Actually,......the L and M model 150's do not have spacers for the spinner installation. The FWD and AFT bulkheads are sandwiched directly on the prop, ahead of the spacer.
James has an M model.

The 150 models prior to the extended fiberglass nose bowl and prop extension DO have shims to preload the spinner.
Attachments
L & M spinner installation.JPG (42.17 KB, 51 downloads)