Dell Laptop SSD help

[dblue42]

I have a Dell Inspiron 15 5000, long out of warranty, which I need to take apart to change the keyboard. I thought I'd upgrade the SSD while I was in there. From the specs, are the maximum configurations an absolute, based on hardware limitations, or can I safely put in, for e.g., a 1TB M.2 drive?

 

A bit new to this kind of thing, the last time I seriously took apart PCs they all had hard drives and SATA was new. Any advice appreciated, thanks in advance.

 

NB - I do need to confirm what is in there, as the spec implies there are two SSD slots, and it only shipped with one SSD in it. The SSD part number is 400-AOTD which is a 128GB SSD, but I'm having trouble finding it. The problem with only having one machine, is the reluctance to take it apart because it does everything.