Are there any existing examples of verses of the Quran etched onto pieces of armor?
Are there any testimonies of verses being etched onto armor? And if so, what were commong verses that were used?
Yes; inscribed Islamic armor is actually relatively common. Here is one example of possible Persian or Turkish provenance now in Baltimore:
http://art.thewalters.org/detail/6002/turban-helmet-with-eye-holes/
And here is an example from the collection of the Metropolitan Museum of Art in New York: