OK, so here I am.
For the sake of entertaining information - SFK stands for Silesian
Scythe Factory, sometimes they were also carrying a FSM brand, which in turn stands for Small-engine Car Factory. I've read (on another forum, though, so take it with a grain of salt) that these two firms were connected, hence both stamps. It all sounds pretty logical for a communistic economy (?).
Less hollow are the surgical ones, they even carry this information on the box - these have stainless steel scales. Most probably for high temperature sterilizing. Hollow ones are named "special" and probably were intended for regular shaving, I believe. But there's also another, fairly rare, incarnation of Wapi - it's called "barber's"; the grind is somewhere between the two above, but the blade is noticeably narrower, 4/8 at max or even narrower. When I got one I was sure it's been worn so much, but the spine wear wasn't showing it and I've seen a few afterwards.
All that Bart wrote is correct. BTW, Aesculap razors have no connections with Wapienica whatsoever, also as far as I remember they were microtomes. "Wapienica" is the name, indeed, not a town.
As for the photo, it might be the "special" one, exactly the kind you're after, Jared. But I can't see too many details on the picture.
regards,
Matt