Roberta Charpentier:
 
Not sure about color variation or thickness indicator of Crown vs.
Cylinder, but pane thickness as an indicator of chronology, given an
adequate sample size, seems to work.
 
References:
 
Moir, Randall W.
   1987  Socioeconomic and Chronometric Patterning of Window Glass.  In
Historic Buildings, Material Culture, and People of the Prairie Margin:
Architecture, Artifacts, and Synthesis of Historic Archaeology,  ed.
D.H. Jurney and R.W. Moir, pp. 73-81.  Richland Creek Technical Series,
Vol. V, Archaeological Research Program, Southern Methodist University,
Dalles Texas.
 
Roenke, Karl
    1978  Flat Glass: Its use as a Dating Tool for Nineteenth Century
Archaeological Sites in the Pacific Northwest and Elsewhere.  In
Northwest Anthropological Research Notes, 12(1):1-128.
 
White, William
    1990  West Point: A Look at the Past Through Window Glass.
Unpublished MA thesis, Department of Anthropology, University of Nevada,
Las Vegas.
 
good luck....ww