I confirmed Brain Buggy is 47pF and 47K ohm. Unfortunately I didn't measure any timing before I decapped the chip. But I just tried using a jumper wire to control the drive motor, and it only ran for as long as I connected it, so I don't think the circuitry extends the drive signal.
The 2 Hitachi dies don't look all that similar, and I don't have any other versions to compare to- I'd like to see the HMCS42 and HMCS43S dies. The datasheets for all the HMCS40 chips show test pins, but the procedures could be different for different versions.