From what I can tell it looks like 475 GT350Rs were made in 2016 with an estimate of 500+ for 2017. Production is planned until 2019 or 2020. So MSRP soon will be the norm.
From what I've heard the production of the GT350R will continue thru the 2018 model year only. It's pure speculation beyond that, unless you know something that is not public information. Getting one at MSRP is laughable. Unless you want a 2016 with lots of miles that has been beat on, that MIGHT be a MSRP car one day down the road. ADM's on new cars are not going down at this time.