United is grossly inconsistent in these type of things. I mean the whole design of the website is different depending on how the wind is blowing--if there's a rhyme or reason to it, I haven't seen it. Sometime I get the old-school blue layout, fonts and icons that the color is similar (at least on my devices) to FT's default blue. Other times, It's the more 'updated' purple layout with the Polaris-looking general branding. The seat maps online sometimes are horizontal, like when checking in, but are vertical, sometimes, when making a booking or checking flight status. Orange is the operative color for F on non-Polaris seat maps from united.com (when just looking at the seat maps from the 'aircraft' tab under the 'day of travel' heading , but those are that deep blue when you're actually in your reservation. But at least Economy Plus is usually a lighter blue across the system, and standard Y is always white...So, there's that.

...And the website still shows the 28J 757-200s (sold/scrapped/retired a year ago). Oh, and it calls the seat "United Business", but directly above that seat map is the 16J 757-200, same seat, same color, but there they call the seat "United Polaris Business".

So, OP...It's understandable why we need some clarification. But if you're on a 777 you will have a lie flat seat...Most likely 'real' Polaris, since the only 777s not configured w/real Polaris are in storage and probably won't be out by then. If you're on a 787-10 or 787-8, it will be the 'real' Polaris. If a 787-9, it's currently a 50/50 shot, probably better by January. *United currently is scheduled to run the 777 on your route until Jan 3. Jan 4th and beyond shows a 787-8, but the January schedule hasn't been updated yet beyond the 3rd. And if it stays as a (general) 787, those frames are often switched between -8, -9 and -10 these days.