Fun Fact, no Davidsons got any filing at all on the bottom bracket, and generally there was almost none on the lugs either. If they look thin, that's from buying (in some cases designing) top-quality castings that came with perfect thin edges, no filing needed. If the edges (shorelines) look clean, that's from super sanitary brazing that left nothing to file. Never any spatter, blobs or lumps. We really had lug brazing down pat, if I may say so myself. After brazing we soaked the flux off in hot water, did some alignment and tapping/facing/reaming, washed the cutting oil off, sandblasted and painted, that's it.

The lack of filing may sound like a cost-cutting move, but IMHO that's even more reason to buy, or rate them highly, because they're WYSYWYG. As opposed to brazing them ugly and filing until they look nice.