Yes, the previous generation of pens (for example those included with the Cintiq Companion 2, Cintiq 22HD & 27 QHD), including the Pro Pen, are compatible with the Wacom Cintiq Pro and will perform as they do on previous generation products. However, the best pen experience will be achieved on the Wacom Cintiq Pro 16 using the Pro Pen 2 that ships with the pen display, or the after-market Pro Pen 3D or Pro Pen Slim. The Pro Pen 2 technology in those pen models provides enhanced pressure sensitivity, improved jitter, improved edge accuracy and other new features implemented in Wacom's latest Pen technology.
Wacom Pro Pen 2 (KP504E)
Pro Pen: KP-501E-01X