Background: As I was delivering some firewood today -- hey, it's been in the FIFTIES here in So. California ... VERY COLD --

my pastor's wife gave me a burgundy Parker "51" aero from her great-grandfather to clean up for her. It has a side breather hole and no date, so I take it to be a later model. (It has a black plastic cap on the filler though.) Finally, this aero P51 has a short plastic *vacumatic* fill tube in it, so someone has been into this pen before.
As I was taking the clip off, this clutch came out of the cap:

Never seen this kind before. So my question is: Is this right??? It doesn't seem to grip the clutch ring very well.
Thanks,
Steve