Yesterday afternoon I posted this in the WRUW thread:
I didn't put it away, back in collection box - for a couple of reasons. I purposely hadn't tightened down the case-back fully, because the gasket was stretched, slightly mangled and needed replacing. Although it might not be immediately obvious from the angle of that photo, it had been fitted with a replacement crystal, whose upper surface sat below the edge of the bezel rim (instead of being slightly proud of it). Later measuring it in situ revealed it was only 1.0mm thick, instead of the correct 1.5mm. Also the pusher buttons were very stiff, probably indicating their O-ring seals were either perished or rock hard. So I decided to give it a quick overhaul, to rectify those issues.Seiko7A38 wrote: ↑Wed Sep 01, 2021 1:21 pm Returning that 7A38-713A to my collection box, I happened to notice that the aforementioned 'second string' example in the adjacent slot had started dancing 'the two-second two-step', so I've just replaced the battery in that one. The dial colour hasn't faded (compared to my previous much better condition example). It's just a poorly lit Q&D photo.
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Before acquiring my almost mint (though faulty) example, I'd bought a couple of others, back in 2017: The one above in average worn condition, which I refer to as my 'second string example' and another in well-worn condition, which was little better than a 'parts watch'. In fact, I'd dismantled it, with the intention of using it as such and never re-built it.
This morning, I attended to the 'second string' example to replace the crystal and pusher O-ring seals. It's not in great cosmetic condition, but as I unscrewed the scuffed case-back, I was irked by the tool-inflicted scratches. Wondering whether the case-back on the other dismantled parts watch might be in any better condition, I dug out the takeaway container where it had remained neglected and almost forgotten, for four years.
It was slightly better: shinier and less scuffed, without tool-inflicted scratches.
Then I noticed its serial number. 
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They're both the same: 783736 !!
For the time being at least ! 
Out of curiosity, I waded through my folders, checking case-back photos of 7A38-713A's, that have been listed on eBay over the last 10 years. I've found TWO MORE with the same serial number 783736 !