Not exactly. We have 1.4.7 textures that have been separated into individual files per the new 1.5 texture rules. Unfortunately, some files are erroneous (Railcraft's items have a white background, for example), and some new textures will still need to be made (new content, new mods, etc.).
Instead of recreating each new texture file, we need to review the ones in the Unstitched folder and fill in the gaps. The unstitcher did nothing to GUIs and mob textures, for example, so those will need to be copied over from 1.4.7. The only thing the unstitcher did was take the spritesheets and break them apart so that there is one file per 16x16 square.
To explain further: I've been reviewing and repairing Forestry this past week. In 1.4.7 the Apiarist's Chest was a 6-sided shape that Minecraft folded to create the proper image. In 1.5 it becomes 6 individual files, but some of the sides need to be rotated to be vertical in the new file (they were upside-down or sideways in the 1.4.7 version). On the other hand, the textures for the ores and many of the items are straightforward and require no work apart from reviewing the unstitched file.