how to identify M6 viewfinder mag factor

[ywenz]

The seller of a M6 classic doesn't know what the mag factor is on the viewfinder. Is there any other way to figure it out? if the factor is not labeled on the viewfinder, can we assume it is a .72x ?

 

[TimF]

Yep. If its other than 0.72 it will state the magnification on a silvered strip at the bottom of the viewfinder finder on the camera's front.

To the best of my knowledge, the only alternative will be the 0.85 finder (of which only a small number were made), as the 0.58 didn't appear until the TTL days.