The production team has used what we have come to call "Model Year Syndrome." We in re-enacting sometimes do something similar.
Progressive Military will often lament, "He thinks all soldiers were sprung full grown from the head of Mr. Davis in 1861!"
When we look through our recipes, housewares, and well... almost everything but clothes... we often fall into this Model Year Syndrome. We forget that we didn't spring to life full grown in 186x, so sometimes our knowledge needs to be outdated for 186x.
Take our favorite food recipes. Many will rely on recipes and cook books published in the 1850s and 1860s. This is a great start, because we can at least document the recipe as being available to some citizens in 186x. But we haven't considered where our portrayal would have learned that recipe. Would our portrayal have learned that recipe from a book or would she have learned it from watching her mother, grandmother, or another female relative?
For my portrayals, I am roughly 40 years old and would have begun a household in the mid 1840s. I tend to rely on recipe books from 1800-1845 to learn what my portrayal would have been making in the 1860s.
I likewise look to housewares with introduction dates between 1800-1850 to outfit my home. my portrayal would not have bought all her household goods at the same time, nor would they have needed replacement at the same time. So, a mix of "Model Years" is appropriate.
This can also be applied to "common knowledge" like home medicine, household cleaning techniques, handwriting styles, a whole host of everyday knowledge. Who you are and how you would have learned what you know are major factors in how out-dated or up-to-date your knowledge is on a subject.
Sure, it's cool to show off the "latest, greatest, most scientific" Widget of 186x to the people we share history with, but our portrayals may have had to be content dreaming of how the Widget would make their lives better, rather than owning one themselves.
Don't forget, too, that just because something is available does not mean it is appropriate for everyone in every situation.
So, Dear Newbie, enjoy a movie that mixes clothes from 1860 with a buggy from 1853 with recipes from 1812 on dishes from 1850 accompanied by music published in 1861. Ah! Much better! So real!