Default [Q] Bought a D800 (AT&T variant), can i transform it into a D802 or D805?

I have recently acquired a D800, but only after doing so i realized that it does not have the main LTE frequency used in my region (LA, Brazil), which is band 7 - 2600mhz

So, after doing some basic research i found out that the hardware inside all LG G2 versions except the CDMA one is in fact identical, the difference between them is pure software. However I have no concrete intel/proof to back this up and i would be much appreciated if any of you could confirm this statement...

Assuming that their (D800, D802, D805) hardware are all the same, is there a way to flash/override D800's baseband modem with D805's modem? Will that work fine or will it brick or maybe even damage the device? Have this "type of surgery" been done in other devices in the past? My goal here is to make D800 work with LTE band 7, so if there is any other way - besides flashing the baseband - to make it real i'm all open ears..

Ultimately if such procedure is not possible bcuz of this and this and that, will i at least be able to flash D802's modded roms (cyanogen for instance) into my D800? Will they work just fine? Or will i only be able to use modded roms made specifically for my D800?

thanks in advance