Omega Speedmaster 176.0015 / 376.804 Case back help

Hi all,
My name's James and I'm a long time lurker on here and have finally plucked up the courage to post.
I have a small collection of vintage Omegas. Among which is this 1970s Speedmaster.
My question is does anyone have any info on this case back. Doesn't appear to have ever had the hippocampus logo on the back and inside a rather intriguing "beta" script.
Any information anyone has on this model in general would be really cool.
Cheers,
J

Welcome! I cannot help but just wanted to say hi, and nice watch! Thank you for the pics.

Thanks for the welcome! Hi! Glad you like the pics. 😀

Thanks for your reply. I also thought that at first but then with some research I found that the 376.804 reference number is stamped in the "normal" case back