Mystery Shirt

So I buy a lot of things from thrift stores. Most of my wardrobe, and most of my raw materials. And sometimes I find some pretty strange things, and I can't help but buy them. But this time I'm really stumped as to where/when this blouse came from. I'm hoping someone clever and costume-history knowledgeable might be able to clue me in.

So I found this blouse, and I initially thought it was from a modern Japanese Lolita company (like Baby the Stars Shine Bright, which has a similar looking blouse here) I bought it because it was $3 and hey, I used to be into EGL long, long ago. I might wear it in a dandy-sort-of way. 

But when I got it home, I realized it wasn't a mass-produced shirt. You can see the wee monogram on the inside bottom hem, and the fact that the hem is hand-finished. The embroidery, you can see on the reverse here, is also hand done. 

Tatted lace around the collar edge

The buttonholes are strange. They are hand made, and horizontal rather than vertical. There's also only 3 of them, and they only go halfway down the shirt. 

Hand finishing on the collar stand. 

Hand embroidery on the ruffle up the front. 

My best guess is that it's maybe from that sort of Gunne Sax movement in the 1970's? I know it's not very old, there is a lot of machine sewing on it, but that's the only other time period I can think of where it would fit. Or maybe a modern lolita with some serious hand sewing skills? 

Also, shoe things are happening! More on this later.