I have tried to twice to get Eotech to repsond concerning technical information. They may have shut down due to Covid? Perhaps someone here knows. I have an older (2007 purchased I believe and no model NO listed on it) that has an NV selection and a QD mount. Is this NV option for use with NV goggles or for co-witnessing a NV scope??? 512 seems (looks like mine) to be a comparable model to mine but mine came with a QD mount. Did ET stop making these QD mounts???