A little more on this ...

Mid-Century materials are more likely than not matte rather than shiny with the exception of metal. You’ll find this to be true in wood finish sheen, in tile and even in paint finishes.  

MCM metals are also likely matte rather than then shiny (with the exception of chrome). If you have original chrome handles and plumbing fixtures in your kitchen and bathroom feel free to keep going in that vein - or to replace them with a more modern matte finish object that you like.  It’s ultimately up to you!