As cool as it sounds to have any machine, especially a LE, left in the box as an investment there is an element of risk with doing this. Speaking from personal experience, I bought a MOPLE that had never been opened and technically was out of warranty and guess what, it had several issues that had never been detected because it had never been out of the box. To their credit, AMD were excellent to deal with despite the fact that I was not the original owner and the machine was technically out of warranty. Michael in particular went over and above what he needed to do.
Just remember that the LEs are amongst the first machines to be made and as we have found out with many new Stern machines, there are parts that end up having to be replaced under warranty such as drop targets, PCBs for example and the issues only come to light once there have been numerous games played on the machines and the problem/s start to present in a number of machines.
Some machines have imperfections that probably should not have passed through Stern's quality control and unless you pull your machine out, you will not know if there are any issues or imperfections that may well be rectified or replaced under warranty.
Not trying to spoil the fun but just something to think about. After my experience, if you were planning to sit on it as an investment, I would at least CAREFULLY pull the machine out of the box, have a good look over it and then put it back to bed in the box. Your audit report/s will show the machine has never been played as well as the fact there won't be any marks or dimples on the playfield, targets and the like. The machine will be worth more to you knowing there is nothing wrong with the machine as opposed to pulling it out of the box and then finding the playfield is flawed, cabinet is marked or scratched and the machine is well out of warranty.