Here you go. The serial number is 5N0568. It says Seiko Stainless steel. 2C21-0350 RO Japan M and it has the Elnix logo. The shop owner told me he thought it was from the Showa era which would make it pre 89. He didn't seem to know though. I looked through the catalogues from 85 and 95 but I couldn't find any watches like it.
Cool look! I'm only seeing the Daini logo, not Elnix. Could just be because I'm viewing from my phone. I'd guess 1985 due to the presence of the logo and the styling, but a more sure way would be to look at the tech guides for the caliber. They often (not always) have a date code on the bottom of one of the pages close to when the caliber was introduced, which might narrow things down further.