The nuvistor preamplifiers also used the RCA 6CW4 miniature nuvistor (as used in the converters) which had a very good low noise performance.
I have managed to obtain one of these rather rare units (according to Tom not many were built for the amateur market). This particular unit appears to be for 2m and has its own built in power supply.
Very little is known about this unit other than it appeared in late 1963 and used a 2N1742. It was capable of 18dB gain at 144MHz and was priced at £1 18s 6d. (One pound eighteen shillings and six pence to our younger readers !)