I dont have the proper answer either, but if you are buying it new, surly should be able to give a proper answer to if the bb area was faced.
In my experience with my troll, I bought it used, but soon after stripped it down completely, partly to learn about outboard bb's, which I had never owned, and also to just go over the whole bike, and at the same time I put some framesaver stuff inside all the tubes while I was at it at that naked stage, as the bike had a wee bit of rust in some places, even though it hadnt been ridden much.
I did think about the bb facing, and asked mechanics I knew, but they didnt think it needed it.
Obviously the frame wasnt new, so didnt have paint and stuff on these areas, so I didnt do it.
a few years down the road, the hollowtech 2 bb has been perfect, not sure how many klicks Ive put on it, and not sure how many were put on it before I bought it, but I suspect the BB has maybe 6, 7000kms. I must have installed it and adjusted the preload properly, as it still spins super smoothly, but I would suggest doing as I did, reading up on all the most trustworthy mechanic stuff and vids, like Parks, and getting advice from a known good mechanic.
I also had the mechanics who checked out my wheelset to go over all the bits , to make sure all seemed well, so thats worth paying a bit for, and shouldnt be much.
Ive always paid a good mechanic to check my work, especially when I started doing things on my own, and I reckon its good to have it checked, and as a learning experience to get tips or advice on if you didnt do something right or whatever, or if an adjustment was off just a bit.
If they know you are planning a touring trip and are on good terms with them, as bike people they will be helpful, and its normal and right to pay for their experience.
all in all, doing stuff on your own is excellent for just knowing your bike intinately, and being more confident of how it will work over time, and how to maintain it well to avoid any issues, and to maximize parts life.
what setup are you thnking of?
bars
cranksets
shifters
9, 10 speed? whatever?
ps, asking around for the best wheel building mechanic with lots of experience is worth paying for, not having wheel or spoke issues is a huge plus, and great wheel prep is the best way to avoid any issues.