RLA Richard Long Bertha original

[artscrafts14]

I obtained an original Richard Long Bertha recently. I opened up the back and the subwoofers have the following marked on them: 18016 67-8525. I'm hoping someone can tell me what I have here. Thanks

 

[ticknpop]

It's either the part number for the cone kit (Eminience likely or possibly RCF) or the driver part number. 8525 is likey the date code for 3rd week of June 1985.
Richard Long pased away in Dec 1986.