Whitelisting for NVMe Drives?

[ToniCipriani]

So I was going through the 260's parts list as part of my future purchase research, I noticed that Lenovo Canada only offers NVMe at 512GB, but the service parts list say there is a 256GB part available:

https://download.lenovo.com/parts/Think ... 151221.pdf

00JT037 1 256G,M.2,2280,PCIe3x4,SAMSG,OPAL
00JT050 1 256G,M.2,2280,PCIe3x4,TOS,OPAL

Wondering if I should just go with the base 128GB mSATA and then swap in a 256GB NVMe myself later. Only thing I'm not sure is that if there's a chance that Lenovo implements a whitelist for the slot?

Also considering the X1 Yoga, which strangely the price is cheaper than the 260 at the same configuration. Only thing I don't like is the 14" footprint, since I'm replacing a 11.6" laptop.