[drcy]

Dark shoes are post 1870s style, but they could be wearing work shoes to the studio and the guy in the right back appears to possibly be wearing the 1870s style. The shoes are the only troublesome detail for me. If they were wearing white shoes, they'd I'd be more more firm that it's 1870s. The general rule of thumb is white hightop shoes (with black trim) are 1860s-70s and black/dark brown athletic shoes are 1880-90s. Dark low tops 20th century. The problem is sometimes the players wore their work or dress shoes or are only in their stocking feet as they're in the photography studio-- but they usually wear their athletic shoes because its part of their uniform.

The guy on the front left is wearing dark shoes, but they look like slip on non-athletic shoes. Official athletic shoes were lace up. And it looks as if the shoes on the right front are also not lace up. And, as I said, the guy in the right back appears to be wearing 1870s baseball shoes. So the shoes are the tough part.

As I said, it could be be early 1880s, but my pick of a decade is still 1870s.

Clearly, December 31 1879 and January 1st 1880 weren't far apart, which is why there is a margin of error, or allowances made, when picking a decade. That's why the word 'circa' was invented.