Speedmaster Help

Hi there Forum.

I've been on here a few years now and thought I had learned a bit but, when it comes to the crunch, I realise I've no confidence in the matter.
I had a meeting earlier and spotted the Speedy on the wrist of the guy I was chatting to. The non pro dial piqued my interest and I asked him all about it.
His dad died last year and he inherited it. He knows his dad bought it around 1969/70 in Glasgow and he has photos of his dad wearing it all the way up until he died.
He knows nothing about it and has no interest in selling whatsoever. I said I'd ask for opinions.
To my untrained eye I think: service bezel, service crown and pushers, totally wrong caseback, wrong bracelet and (possibly) wrong hands. He hasn't opened it up so doesn't know movement.
It's losing about 5 minutes a month so I've advised he gets in touch with Simon Freece for a service.
He still has a few rooms of his dad's place to clear out and hopes to find the box etc but I imagine, from the looks of it, Omega serviced it at some stage and replaced a load of parts.
Any idea on reference etc? Apologies for poor pics but they were snapped under awful light in the meeting room.

Cheers. Hadn't considered the case bearing in mind the guy is adamant that it was purchased between 69-70. He also remembers a different caseback. I showed him a hippocampus one and he immediately said that is what he remembered. I guess I'll advise he gets it to a watchmaker and see what's inside.