Well, at least we know that Marshall Meyers took the picture.
A composite photostat of the Hegemann/Peets pages?
The edition of Il Campo Marzio within Penn's Fine Arts Library contains the Ichnographia Campus Martius in its first state. The photostat is of the Ichnographia Campus Martius in its second state. The Hegemann/Peets reproduction is the Ichnographia Campus Martius in its second state. This is all still the workings of conjecture.
The correlation of the Ichnographia Campus Martius and the 1961-62 Market Street East plan is the real point of investigation.
from MoMA's exhibition archive:
This is a very interesting (clay?) model in that it is a 3-dimensional negative/void rendition of the Market Street East plan/study--a mold, perhaps, for a cast 3-dimensional positive/solid rendition of the Market Street East plan/study?
Curiously, Piranesi's actual drawing/engraving of the Ichnographia Campus Martius was done in the same negative/reverse way.
also from MoMA's exhibition archive:
The presentation of architecture over a very enlarged pixelated 'negative' rendition of Piranesi's Ichnographia Campus Martius.
The Koolhaas/OMA use of the Ichnographia Campus Martius as 'floor paper' (not wall paper) occurs in several projects, but the one project (that I know of at least) where the usage went from schematics through to execution is the plinth of the CCTV Headquarters.
The ICM 'floor paper' usage still occasionally occurs in more recent projects as well. And there's a little more 'background' on the subject here.
OMA wins Axel Springer Berlin HQ competition
Note the Ichnographia Campus Martius used as floor paper again.