From what I have learned it depends what your doing with your gun. For a hunting rifle you should sight in for a cold bore shot because your not shooting a bunch of shots. If its a target rifle you should sight it in with a warm barrel due to shooting a number of shots.
Not knowing all the technical stuff, I would say there is. All the Sniper shows I watch show them concentrating on that cold bore shot. Heat makes metal expand so it only figures that accuracy would suffer somewhat when the barrel warms. But how much, like has been said before at ranges under 300yrds probably not much, depending how well the rifle is built.
A heavy barrel can deal with heat from consecutive firing better than a light, or thin profile barrel, which will vertically string shots as it heats.
I've heard of shooters leaving the barrel of their precision rifle fouled. If I recall correctly, this is supposed to provide a more uniform and reliable surface than a barrel that has been cleaned after each shot, or shooting session.
With a barrel that has been properly cleaned, ( leaving a very light coat of oil in the barrel ), I always run a patch of alcohol through the barrel prior to shooting followed by a dry patch. The alcohol I use is the common CVS stuff. I have found, not doing this, will effect my first few shots before the barrel warms up and all of the light coat of oil is shot out.