Color PostScript documents are coming out of the printer as monochrome when using the mswinpr2 output device to an HP Color LaserJet 3800 PS and a Savin CLP27DN PS.
As discussed on the phone, the problem is that the particular printer driver that reports BitsPerPixel == 1. Ghostscript thus selects a monochrome (dithered) device. The command line option to override the Windows driver setting is -dBitsPerPixel=24 (for best RGB color). Note that the -dBitsPerPixel=4 will also product color, but it will be dithered by Ghostscript, so the quality will be much lower than what the optimized color rendition logic within the printer can do. The -dBitsPerPixel=8 setting also produces color, but it is still dithered, just with 2 bits per primary, so it will be better than 4, but not as good as 24.