for sony 8x dvd+r media all made in japan spindles will be TY.
i don't buy -R so i'm not up to date on that and i think the 16x vary. we used to think that an octagonal spacer meantit was definitely TY and a circular spacer meant sony, but someone disproved this before. it's probably still likely, but not 100%.
I've NEVER seen any case of sony dvd+R 8x MIJ NOT being TY though.