The best I can say is that ATF personnel said that they would process those applications.
I'd be nervous about ATF backtracking and saying, "turns out we didn't have authority to look the other way" or some liberal judge saying that for them. I'm certain I'm overly cautious about this whole mess but we wouldn't be in this mess in the first place if they weren't making up stuff as they go along. There is way too much discretion (their word) going on here.
If it was me, and I was going to file with an imported braced pistol, I would wait until the last few weeks, just in case the whole thing goes away in the meantime. But that's just me.