Unknown, and probably not supported by Adobe. You may have to try it yourself using the trial version of Lightroom, if necessary.
There are other ways to migrate from Aperture to Lightroom by exporting files from Aperture, but if you want all of your metadata, masters and previews, you'll need to use the plug-in. However, some metadata and previews are not coming across as intended, so Adobe is not quite there yet.
What kind of "files" do you mean, exactly?
By files I mean master images and previews. You can still the Aperture features to export masters and previews. You'd probably want to export into some sort of folder hierarchy that maintains project structure and/or dates. By using export presets, you can choose to include metadata. You'd have to run two passes, one with masters (required), and one for previews (desired).
John's guide is the best I've found, and includes about 90% of the information I previously found for my punch list.
Your best bet is to try the plug-in first, though. For some, it may be well worth the expense to upgrade to Aperture 3.0 if Lightroom 5.7 and Aperture plug-in requires Aperture 3. I'd upgrade only because it would save me hundreds of hours. But others in the forums have only used Aperture as a photo repository, with little effort given to organization. In that case, it would not be worth the upgrade.