`copy-file' does not keep time although KEEP-TIME is t when one copies a
file from the local computer to a remote one using Emacs Tramp from
today's CVS.
When I look into tramp.el it seems that copying is handled by
`tramp-do-copy-or-rename-via-buffer' and that this function does not
support KEEP-TIME. It seems that `tramp-rcp-program' is not used at all!