Sudek "Profily" pictures

Just bought some nice Sudek pictures at a Swedish auction for not that much money (~$150). It is 18 pictures that look and feel like silver prints and really well printed, but I suppose it could be something else. (photogravures?)

It would be interesting to know how these kinds of portfolios are usually done. It is probably quite a large number of copies. Are they made from the negatives, or with some intermediate negatives if they should need burning/dodging etc? Or are they more likely reproductions from original prints?

/matti

At the bottom of the site it says (in English) silver prints. Unfortunately I haven't an inkling what the rest of it says.
I believe most portfolios were individually printed.

Unfortunately the rest of the text doesn't say anything. And when searching on the web on the same portfolio some places say it is bromoil prints, which it certainly is not: Here and here.
Other places say silver prints, like here .
Is there a way to see the difference between photogravure and silver gelatin?
/matti