I think you should refer to my friend, a Seiko watch collector and he knows his stuff.
He ever told me the movement usually made in SG, Malaysia or China. The case is made in China and the watch assembled there unless your Seiko is a Japan Domestic Seiko or certain series then likely fully MIJ. There are ways to tell where the watch is made but I forgot liao.
I think you can email him for clarifications, this is his blog: