Possible to enable RAW printing for only jobs being sent through cups-lpd?

[John Five]

Is it possible to enable RAW printing for only jobs being sent through
cups-lpd? I say this because, in our environment, anything that comes
through LPD has already been processed on the Windows client side by a
native Windows driver (most of our printers are HPs), so it should be
safe to pass on this data to the printers with no further processing,
shouldn't it?

How would I finesse CUPS in to doing no further filtering on jobs coming
through cups-lpd? I do not want to delete the printer's PPD file since I
would like it to be there for filtering jobs coming through Samba. Would
adding the following line to the cups-lpd xinetd config file do the trick?

server_args = -o document-format=application/vnd.cups-raw

Thanks in advance for any tips!

PS Most of our OS X clients also send data through LPD.