An original Maserati 4CM has come up for sale in the UK. The image below shows that the car is available through Tom Hardman. This advertisement was placed into one of the UK's main classic car magazines in January.
This one looks like it is a pre-cursor to the 6CM and seems to share a similar front end - the early ones had more of a square or rectangular grille. The 4CM and related 4 series racing cars were built during the 1930s.