Depends how you look at it.
WP has not been very popular at all so far, and thus i doubt any carriers are actually that fussed about WP8 (regardless of which phone).
I would wager Microsoft and Nokia are throwing money around to get carriers excited by their phones. Do Microsoft just throw money at every carrier, and none bother to promote WP8, or do they target specfic carriers, so the carrier promotes WP8.
Don't count on carriers not being fussed about it.
Android costs them a lot of extra money annually due to support issues. Google updates the OS, but the carriers have to work on deployment. They also have to do tech support issues, most of them stemming from interface differences between the manufacturers. There's now also concern about the platform due to the Samsung lawsuit.
iPhone is also expensive due to Apple's demands on the carriers.
Then back to the Samsung suit - the carriers may not pay mind to WP8, but manufacturers will in increasing numbers. MS can offer them protection from Apple's lawsuits.
But ultimately, the WP8 model is probably the one that helps the carriers the most. They have a big partner that requires the consistent ecosystem of the OS be maintained. MS will deploy OS updates directly while giving carriers the ability to create custom apps and hubs for the their customers.
The reality of Windows Phone is that it will cost carriers less in support, will cause less technical issues, and will not have the same kind of high demands as Apple. This is why Verizon is going all in. The corporate sales guy I know has said to me that VZW's goal is to have over 50% of all their smartphone sales be WP8 devices by the end of next year. They will be particularly pushing to move iPhone users with special offers. The money saved by having more WP8 subscribers will help their bottom line and also allow them to spend even more on enhancing their network.
This is the pitch MS made to VZW earlier this year for an enhanced presence and they loved what they saw.
And for carriers like Samsung, it will cost less to license WP8 for a device than the patent fees they pay MS right now on their Android devices.
I fully expect an onslaught of ads at the end of the year and exclusive offers for those who switch to Windows Phone as enticements. VZW wants to populate their stores with WP8 devices and lower the amount of Android devices they carry.