1. The minimum hardware req't per nVidia is a 500 watt PSU andIt calls for an 8 pin cable. In short. with the Armor having the same power cab;le configuration, this tells us that you basically have the reference PCB.
2. Telling me that you have a Rosewill 500 watt PSU is like telling the auto parts guy you need parts for a blue chevy. Some of Rosewill's PSUs are made by Superflower, one of the best OEM's out there ... other are made by Solytech ... one of the scariest ones out there.
3. That is not the only way it could catch on fire as evidenced by the EVGA 1070s link above. The approach I'd take is to look at your PCB and see where the burning is, if it matches the EVGA problem you'll see in that link, Id go w/ that argument....inadequate VRM cooling.
The problem here is that when folks ask "what's the difference betwenn A & B ?" ... many forum users will post an authoritative sounding response and say:
no backplate, might sags
one less heat pipe
Twin Frozr V fans (gaming x has Twin Frozr VI)
100Mhz Lower boost speed
no leds
Let's look at the MSI 1060 Gaming versus Armor
https://www.techpowerup.com/reviews/MSI/GTX_1060_Gaming_X/4.html
https://www.techpowerup.com/reviews/MSI/GTX_1060_Armor/4.html
In addition to the above, we see that on the Gaming X There is a second metal plate w/ thermal pads, which provides cooling for the VRM circuitry and memory chips.
The Armor uses a uP 9511 voltage controller; the Gaming X uses the uP 9509P
So yes, if you can confirm that the VRMs are where the "fire" occured, I'd use the EVGA argument that the Armor is deficient just like the EVGA SC model. EVGA is replacing the cards that went up and smoke and offered a thermal pad fix kit . perhaps you could even get a local PC shop to examine the card and identify with a letter saying that the VRMs failed.
You might even offer "to pay the difference" for a Gaming X model that has the thermal pads and heat plate.
But next time you ask a question about which card to get on a hardware forum and the respondents write "they are all the same, just get the one that's cheaper", remember this lesson.