Yes, for the most part you can reconstruct the circuits from the photos. (Which I'm doing.) A key thing that doesn't show up is which transistors are enhancemen

Yes, for the most part you can reconstruct the circuits from the photos. (Which I'm doing.) A key thing that doesn't show up is which transistors are enhancement and which are depletion; this depends on the doping. It's straightforward to figure this out from the layout, though. Except in the Z80 processor: the designers famously used some depletion transistors in unexpected places as "traps", so anyone who tried to clone the chip visually would encounter subtle failures. I'm pretty sure that 8086 didn't do that, though. The other aspect of your question is there's a lot of implicit manufacturing knowledge that you'd need if you tried to reconstruct the chip. Things like the resistance of the lines and the characteristics of the transistors that you'd need to get right for the chip to work reliably.