This is likely the GC-1, but the lack of model identification does not rule out the possibility of it being an unlabeled GC-2.

Beckman Instruments entered the gas chromatograph business in 1956 with the acquisition of the successful Watts Manufacturing Company. Later that year, Beckman Instruments produced its first gas chromatograph, the GC-1, which was intended for laboratory use. Shortly after, Beckman Instruments produced a line of gas chromatographs for industrial use, which offered both automation and customization. These instruments were used by the petroleum industry and in the fight against air pollution.