I've googled around a bit and found both "yes" and "if desired" answers to my question: Should a steel frame's bottom bracket shell be faced?
I've stripped my frame down to apply Framesaver and the last component to come out was the bottom bracket. It's a Truvative Gigapipe so it's fitted with lock-ring type flanges. Once i got out of the frame i was a bit surprised to discover that the BB shell hadn't been faced! It's a LeMond Poprad that's only a few months old (bought in May). The threads seem clean so i assume that they've been chased.
So, should I cart the frame off to the LBS and have them face the BB shell? Man, it's Friday and i have the first 'cross race of the season on Sunday...
Rans Enduro Sport, Hase Kettweisel Tandem, Merin Bear Valley beater bike
I've never worried about it and I've never had a problem with it. If the frame was recently painted you might want to be sure it doesn't have a drip or something that will keep the BB from setting square on the shell.
I'm not too familiar with Truvativ stuff, but if it's an external-bearing BB, then facing is a good idea, maybe even a requirement. If it's an internal, loose-ball BB, then it's also a good idea from what I've read.
If it's a cartridge BB, or a BB where the cups don't actually touch the faces, then it's less necessary. In the case where the cups don't touch the faces, I see no point in doing it unless and until you change over to a BB that needs it. Otherwise the facing is just going to take the paint off (if any) and it will start to rust.