  Recently, a method for O(a) improvement of composite operators has been
proposed which uses the large momentum behavior of fixed gauge quark and gluon
correlation functions (G. Martinelli et al., hep-lat/0106003). A practical
problem with this method is that a particular improvement coefficient,
$c_{NGI}$, which has a gauge non-covariant form, is difficult to determine.
Here I work out the size of the errors made in improvement coefficients and
physical quantities if one does not include the $c_{NGI}$ term.
