Oh, they’re very much a period detail! I mean, not every single lady of the Victorian era had them, even though they might have had curls or a curly hairdo. But they’re appearing frequently enough in 19th century depictions of women for me to label it perfectly period. Here’s three depictions, of Adelina Patti, Christina Nilsson and an unknown woman:
This is a really interesting question actually, and is a really good example of how quickly fashions and sensibilities can change really quickly!
These are all pre-1878 post 1867-ish. This is really the era most phantom costumes are based on- or fashion plates are tweaked to resemble this period even if they are later.
Actual c1880 hair fashion was for hair close to the head and in a low bun at the nape of the neck (maybe a loose roll and or flowers back there too). The style was definitely on the whole very restrained and to have hair loose was not the done thing even for young unmarried ladies.
Madame Giry is the big standout from this trend. Her skirt and bodice are so 1890s- hair is a weird mix of early 1870s basic shape but 1880s severity and 1860s sheen. Gored skirts like her are post 1890. So she is smack bam in the middle of the transitional era from bustle to umbrella skirts. Her shoulder cape in Masquerade is also bang from the 1890s- it’s the actual shaping, the shoulder caplet is appropriate for 1880 but is much more fitted then and the skirt should be more tubular.
But back to the little loose curls 😉 As you can see above you have examples of the soft curls that escaped from a loose upsweep (Kristina) and tiny super tight individually styled curls. But then there was the fake fringe/bangs. Lets hope that never gets incorporated in to the show.
That fashion came about as women did not want to cut their hair for a fad and so wore a fake hair piece at the front. And given frizzy curls were the specific fashion… they look like headbands of sheepskin.
I used to be able to identify fashion plates not only to a year but a season and occasion. And sometimes even a month or date.