Jars could be warmed but don't need to be hot. With jam, there could be considerable thermal shock which could result in cracking or spalling into the product. Jam is filled hot to create a sterile, vacuum seal with the lid, also. There is no problem like this with honey. I usually wash the jars in the dishwasher and sterilise in the oven, stand them out, allow to cool and fill with honey. But I don't usually do hundreds of jars and my empty jars may have been stored in cardboard boxes for some time. Ymmv.
If honey is warm it will help to allow entrained air to rise to the surface. For 'show' honey there are several methods to prevent 'frosting', one of which is to make sure all is warmed afterwards to be sure honey has not been poured onto a cold surface which may cause 'frosting'.
