>>96312557
Yeah, the blazoning doesn’t mention shading/highlights, or any number of other specific details. It's up to the artist (likely with some input from the client) to decide in which style exactly the specific depiction of the coat of arms he's creating will be executed.
Though I guess this also draws up another important point: devices on shields needn't be specifically heraldic.
>>96313094
If there was time and money for it? Absolutely, if that was what was in fashion at the time. Same with silks, velvet, gilding, etchings, etc. Showing off how rich you were was just as Big Fucking Deal in war as it was in peacetime.