  We investigate possible a-priori "imprinting" of general relativity itself on
spaceraft-based tests of it. We deal with some performed or proposed time-delay
ranging experiments in the Sun's gravitational field. The "imprint" of general
relativity on the Astronomical Unit and the solar gravitational constant
GM_\odot, not solved for in the so far performed spacecraft-based time-delay
tests, may induce an a-priori bias of the order of 10^-6 in typical solar
system ranging experiments aimed to measuring the space curvature PPN parameter
\gamma. It is too small by one order of magnitude to be of concern for the
performed Cassini experiment, but it would affect future planned or proposed
tests aiming to reach a 10^-7-10^-9 accuracy in determining \gamma.
