If you are looking to update the look, I would take them down.
If you are looking to shhowcase the house as a retro homage to the period then you will have to go BIG with period appliances, colors, furniture, etc ...
Decorating is about making a statement for a purpose.
For my taste, I would update if you are looking to sell. Let the bones speak for themselves, make sure everything is in good repair, newly painted in contemporary colors, and FRESH (no musty odors).
Honor G-Ma ... make her proud.