Here is my Seiko C359-5010, this one shares the same module as the better looking on here on this page C359-5009 (Subjective) however it came up for sale very cheaply because it was missing the battery hatch. Seller said it was working when a battery was held in place. I made an offer and a few days later the watch arrived. I set about finding a hatch so reached out to my Facebook group and a few others I am in. Sure enough a fellow Seiko enthusiast in Australia got in touch and posted a spare to me. How kind (Thank you Max)
within a week it had travelled all the way from the other side of the world to my doorstep where it was fitted. It was missing the rubber gasket so I used some plumbers tape which does the same job.
Watch is working perfectly so I just gave it a good clean and light polish. Very happy indeed to complete the set of these. This example is from 1979!