LTE Band 12 support on Lumia 640 series devices

Question

T-Mobile USA recently began to offer service on LTE Band 12.  Many of its newer devices support Band 12.   I have been reviewing the specifications for the new Lumia 640 devices, and am very surprised to notice that the "LTE Dual SIM" versions of the 640 support Band 12, but the non-dual-SIM version -- i.e., the model that T-Mobile USA itself will be selling -- does NOT list Band 12 support.    
I'm hoping that the device actually does have the hardware to support that band and that the reason it's not being listed is for regulatory reasons.   If that was the case, then presumably the capability could be enabled by a software update at a later time.  
Band 12 support is something I am looking for in my next phone and this will impact my purchasing decisions.   So with this all in mind, a few questions:
1.  Does the T-Mobile version of the phone have the hardware capability to eventually support Band 12?
2.  Will the dual SIM LTE version of the 640 work on T-Mobile's band 12?

Answer 1

Models sold in the US often have different hardware than those sold elsewhere in the world because US networks have a habit of doing things their own way in complete deference to the rest of the world. The only other country that has its own hardware variants these days is China.
You will have to check with T-Mobile if their variant has any different hardware than other US variants because the specs on the Microsoft web site are not likely to show it.
Band 12 is not T-Mobile's, it is the same Band 12 that every other network uses, if you can get a model which supports that band then it will work.