Unless Ford does something significant to distinguish the 2015's from the 2016's, these will not have much of a premium (except initial purchase). In a few years, they will just be another GT350, maybe a slight premium for being first year but nothing really special to make them highly...
More colors are coming, you just may have to wait if the color you want is not part of the initial introduction. Ford is going to leave some colors for future releases to keep up the interest and for special editions.
These are not investments, buy other things for investment and buy these cars to drive, period.
In 50 years, they might be someone collectible, if you have invested right (real estate, etc.) you will not care.
There are much better places to invest your money over the next 50 years if this is all you are worried about. Buy some real estate for investment and purchase a car to drive and enjoy.
Since R comes with Track standard, doesn't it look like you can actually buy an R model with more options than a base GT350? Track + Tech where base you can only get one or the other?
I didn't expect Ford to drop a GT350 in 2015 but it looks like they will build 137 of them.
The next question is what is special about the 2015 vs the 2016? Buyers of the 2015 are likely to pay a large premium to get one, unless there is something special about the first 137, they are end up...
Logic would say otherwise. 2016 order banks open in a few weeks, everyone will be jazzed about getting a 2016, the first GT350's will not be delivered until later in the fall or winter. Everyone will be selling 2016's and even previewing 2017's, by then I don't see an "old" 2015 coming in...
While similar in blue shades, Guardsman Blue from the 60's is a simple enamel paint while Liquid Blue is a very special multi-layer show car paint. I think a lot of the excitement stems from the fact that you can't get it!