Probably.  The G-M tube selected is very sensitive to alpha radiation.  This allows a high number of events (counts per minute) without needing to use a source with high beta or gamma activity (dangerous).  It is very possible that cheaper less sensitive tube will also work depending on the radioactive source and the throughput of random bits required.  I intend the design to use a simple two pin connector for attaching the tube using soldered on leads, and an adjustable high voltage power supply so the design could be adaptable to other tubes which operate in a 300V to 500V range.