Yes, I have been using them successfully with my AT&T G3.
The flip-over cover annoyed me, so i carefully cut it off. I am disappointed that they do not offer a back without a front cover with Powermat charging, but I am sure that they will in due time, both LG through AT&T, and third parties. That place on eBay referenced here that sells all sorts of backs sent me a note stating they are working on one for the AT&T version with Powermat charging, and to check back in in a couple of weeks.
Of course it would have saved us all a lot of hassle if AT&T would have just put the Powermat charging sticker in the stock back to begin with!!
I was at first disappointed and annoyed that AT&T went Powermat instead of Qi, since I already had 3 Nexus Qi chargers for my Nexus 5. But I actually kind of dig them, the charger itself makes an escalating noise when charging is initiated, and a descending tone when charging is stopped. That is very helpful when the phone is on silent or vibrate and you do not get an audible tone to confirm that it is charging. With my Nexus, sometimes it starts charging then stops, and you come back to get it and the phone is not charged. If that happens with the Powermat you at least get the audible tone. I have been using an LG G3 watch since early July, so I often have my phone completely on silent.
BTW, don't pay $50 for the charger from AT&T. Go to Amazon or eBay and buy a Duracell Powermat charging kit for the iPhone 4/4S, includes a Powermat charger and a Powermat iPhone kit, and throw away the iPhone case and keep the charger. I bought some as low as $5.95 for the Single Charger.