No, because changes made by serving agents would only be seen by posting
agents. Serving agents do not sent messages to any other news server.
Only relaying agents do that.
Ah! I see! We carefully said that the order of the steps in the various
"Duties" sections could be varied so long as the final effect was the
same, but we omitted to say the same for the order in which serving and
relaying were done.
You could cover it in the definitions section 1.4 by saying:
'A "relaying agent" accepts articles from injecting agents, serving
agents, or other relaying agents and distributes them ...".'
possibly with corresponding tweaks in the varius "Duties" sections.