I can’t believe anyone would dismantle the H127 as you suggest and another one would be needed to get the white hands! Mine has a clear plastic dial behind the hands and your white one does seem also to have a clear dial with a white sheet behind it so I suppose could be possible. We would need to find one like mine in an old Seiko catalog or advert to prove it is original.
The model numbers of my watches from left top are as follows:
(The sports 100 dual has numbers removed)
CITIZEN 8988 001962Y GN-4-2-12
I have owned the H557 since new in about 1980, bought duty free in Dublin Airport. It was worn every day for over 25 years including swimming over a mile per week for much of that period.
This made me realise how good these watches are and led to the above collection, mostly purchased recently as badly scratched and/or non runners needing batteries.