The reason I asked is that the fit of the rifle is important with iron sights. You don't want to have to force your head down to line up the sights, or worse, to not be able to get the front sight down into the rear notch.
The only M12 I have held had no sights, but the synthetic stock had a very straight comb, like the Browning X-Bolt, set up for a scope. Photos of the walnut stocked M12 with open sights appear to have some drop on the comb, but I have not looked up the dimensions. The older Steyr Mannlichers, like any of the older rifles, had more drop than modern rifles, and the open sights align naturally and quickly. My 2014 Prohunter has enough drop on the synthetic stock for open sights, and the Classic and the SBS Forest are even better, yet both work as well as anything with the scopes, too.
If there is an outdoor show where you can handle and aim them, to check fit for yourself, I would urge your doing that.