What is this Omega? Is it worth servicing?

[moofur]

So my mom was cleaning out her cupboards and she stumbled upon this vintage Omega that she got from her boss a long time ago when she started working. I have the box and all paperwork including the original purchase receipt, date of purchase, serial number, etc.

I couldn't find any markers on the underside of the watch, but the receipt is dated November 20, 1977. The gold strap that the watch is on right now isn't original, but I have the original leather strap as well also in mint condition (pictured).

Is it worth restoring? The watch is in pretty much mint condition since my mom has never worn it for the past 30+ years. However due to its age it obviously would need some servicing.

Any insight into what it actually is would be really helpful!