I have been trying to dig up some info on this lens, I haven't come up with much other than the design was by James Gilbert Baker.
The field is supposed to be highly corrected over a large angle with minimal vignetting, but I can find no reference to it being apochromatic. Some aerial lens designs had their seidel aberrations optimised at the expense of achromatism, and so required the use of a coloured filter to keep them sharp.
It is not suggested that this lens is of that variety though.
An interesting and highly desirable piece of optical history.
fwiw) Here are a few more pictures.
http://www.flickr.com/photos/50231105@N03/