Yes, it will.
It will completely depend on the magnifier, but if you are asking about the EoTech magnifier then yes it will still work because the EoTech magnifier will come with as a standard height and will include a riser to accommodate the EXPS models that have been raised.
The brightness is adjustable, the "on/off brightness adjustments" description refers to the fact that the brightness controls are also used to power the device on or off.
The Eotech 512 will fit and function on your VR80. It easily installs to any picatinny rail.
This will work fine on a 12gauge.
This will work fine on your 12gauge it will not shorten the lifespan of the optic.
Yes, once you mount the optic you will have to zero it as a set distance.
Besides the sticker, the only difference is in the accessories that come with the item.
Yes, it will and you would want the standard model that does NOT include the riser. The standard 512.A65 is set at an absolute co-witness height.
Yes, everything we offer is brand new. The only time it will not be technically "new" would be if the product is labeled "DEMO".