I made cross-checkings for Shoda-san's measuremets of "SPARE MIRROR" at Kagra site.

1) OSEM flag position on mirror

Within the accuracy of 1mm, these measurements are almost consistent with the design.

Only a measured value of the upper edge of the mirror was wrong.

2) Relative position of OSEM flag respect to the through-hole

After the hanging, it seems that the mirror is placed on 6mm upside from the mirror box.

I confirm it by making a drawing as attached.