No they are untreated posts
Oh I will add here too is that you can tell if the posts are treated as all treatments for termites etc turn the wood a bluey green colour too here in Australia anyway. But always good to check so you don't poison yourself with your winter fires.
Here in the US treated post are also called "Criso Posts" short for Creosote treated post. Electrical power poles, rail road ties, pallets and fence post used by farmers were treated with Creosote and other chemicals for over 100 years... well into the 90's.
These treatments usually included a heavy dose of "Arsenic". The arsenic protected them from just about anything that crawled or walked. The use of arsenic wasn't discontinued until 2003.
I cringe when I see anyone use an old treated post in a garden or anywhere near food or medicinal plants or use such wood for firewood. I know where there is a beautiful patch of Yarrow, around the base of an old electrical pole... I won't touch those plants despite the fact it's the largest and most accessible patch of yarrow within 30 miles of here.
Example… about 10 years ago I was making and selling high quality charcoal at the farmers market. One night I clicked on a youtube video, a guy showing people how to make charcoal from old wooden pallets.
They weren’t treated with creosote but by their color I knew his pallets were treated, most likely with arsenic.
I emailed this moron and politely included some informative links about what treatments pallets received. I promptly got a rude “You don’t know what your talking about” reply… sad…