Unfortunately the use of powdered hair or powdered wigs went out of fashion by the 1790s, so even if some people were holding on to the fashion for a little longer it would not have reached near the 1839 date for practical photography. That being said, there were more lax standards of museum conservation and you might find photographs taken later of people wearing 18th century clothing, though I have yet to find any of those wearing the original wigs or proper hair. Some original wigs do still survive, as do many detailed descriptions of how to make and use the different pomades and powders. If you're looking to better understand the process there are people who are currently researching and reproducing the process of historic hair care and styling.