Another newbie question - Was there ever made a device I would call a preview lens? What I am thinking of is something small that could be used in the field to check composition for a potential photo without dragging out and setting up a camera - sort of like what you see a film director use to get an idea of what the camera will "see". I have recently acquired a Crown Graflex with a 135 mm lens. Thanks!

What you want is called a director's viewfinder, but most come in motion picture aspect ratios which aren't close to 4x5. Some have adjustable aspect ratios.

I've never done it but people on the LF forum have recommended using a piece of cardboard with a 4:5 hole cut in it. Go here: http://www.largeformatphotography.info/forum/ , search on "director's viewfinder" and "cardboard frame"

I recently picked-up a copy of the navy photographer's mate handbook circa 1966 and noticed that one of the graflex cameras had a removable view finder to be used as a preview lens. Wondering if anyone know which model and if one might be available from a "parts only" body.

Does your Crown Graphic have the optical viewfinder mounted on top of the camera body? If so, this can be removed and used on its own. The no. 4 viewfinder mask is the one to use with a 135mm lens:
http://www.graflex.org/speed-graphic/viewfinder-masks.html
If your camera has the top-mounted viewfinder, it might already have the no. 4 mask installed.

Thanks for the comments.....I think what the navy is talking about is an earlier model - one with a separate view finder (on top) and range finder (on the side). My camera has both range and view finders in one piece on the top. If this is correct, what are the chances of finding a pre 1955 view finder to be used as an "in your pocket" preview device?

Viewfinders show up quite frequently on the auction site, e.g. there's one right now:
http://www.ebay.ca/itm/CROWN-SPEED-GRAPHIC-GRAFLEX-CAMERA-TUBULAR-FINDER-/290600061651?pt=Film_Cameras&hash=item43a91d0ad3

Billy - Thanks for the suggestion. I found it and it is soon to be mine. :-}