Is there test data for 120V receptacles exposed to continuous overvoltages?
I would advise you to satisfy your question through some tests that you could do.  The basis for your question is an "empty receptacle" which is one where no load is connected and no current flows.

Start with a new receptacle of a similar type.  Using a Meg-Ohm Meter at 500 v and 1000v measure the resistance from Hot to Nuetral and Hot to any metal surfaces on the device (ground).

Source a simple step up transformer such as this https://www.digikey.com/product-detail/en/thomas-research-products/120-277-275VA/120-277-275VA-ND/7318416

Connect the transformer to 120 v and the secondary of the transformer to the hot and neutral of the receptacle.

Disconnect the receptacle and re-do the megger tests at intervals of a day/Week/2 Weeks.

I doubt that the result of your experiment will result in any breakdown of the resistance of the receptacle.

Now if the case of your fire was the result of a load being connected to the receptacle and it wasn't empty - as in you are being lied to - that would bring up an entirely different set of questions and cause for failure.