Double Bass 1966 Ampeg B15N with an 8 pin speaker connector?

[B15Nsteve]

Hoping Im on the right sub-forum for this question; please forgive me if I'm not
Question: my Ampeg B15N appears to have been built in 1966 based on its cab sticker serial number. Is it odd that I have an 8 pin speaker connector instead of the 4 pin XLR? I thought the 8 pin connector was used way prior to 1966. Thank you.

 

[bass player 53]

Did you look in here?

https://www.talkbass.com/wiki/ampeg-portaflex-wiki/

 

[B15Nsteve]

Did you look in here?

https://www.talkbass.com/wiki/ampeg-portaflex-wiki/

Thank you

 

[B15Nsteve]

Thank you

Based on your help and my misread of the B15N's serial number, what I thought was unusual older features on a 1966, turns out that my B15N is more likely a 1963 than not …an Occam's razor solution… stupid me!