mine (Dec' 02) doesn't have an RS inlet either (does anyone know if there was a period of production during which they were fitted, or is it a random parts bin job?)
(^) to check for them, you need to remove the fuel rail guard - there'll be a big 'R S' cast in the lower inlet if you've got one; can't miss it but it's worth a quick search for a photo so you know what you're looking for. the RS inlets supposedly have slightly larger/cleaner ports