Mare Island Naval Shipyard Career Retirement screw back pin Gold and blue enamel

Up for auction is an Very Rare Career Retirement pin from Mare Island located in Vallejo, Ca.
In my entire time of collecting Mare Island memorabilia I have never seen another for sale or even another in a collection.
The pin itself looks to be gold with blue enamel. The post and screw back looks to be original with the same metal type and patina on both. There looks to be a couple of very fine scratches above the "ET" in "RETIREMENT" on the Mare island crest.
There are no pits, corrosion or dents in the pin at all. The enamel is fully intact with no scratches, cracks, color loss and still has its original shine.
I grew up in Vallejo, CA and this pin was purchased in a yard sale in Vallejo in the early 90's so I am unable to tell the age of the pin itself. I also cannot be sure of the recipient of the pin. (Military or Civilian) I do know that I have a family member that retired from Mare Island in the 80's as a civilian (over 30 years) and their pin was not as nice as this one. (Theirs was a flat pin in the shape of the Mare Island Symbol with an pin back.)
Any questions please feel free to ask!!!!!!