The crop factor is set by the camera in proprietary metadata. The raw image is presented to non-Pentax software as a full-frame capture.
Regardless of whether it is easy to get this metadata (with or without some SDK) there is little wisdom in chasing proprietary metadata unless there is a real benefit. So, it is common to see proprietary features like this slow to be supported by third-parties.
The camera manufacturers should really decided on standard metadata for this stuff, instead of obfuscating it in the maker notes (or whatever.)