Regardless of what "Mr Haynes" or owners handbook says I think all V6's are around the 600 RPM mark on tickover.
Mine is, other people I have spoken to, theres are, and the number you see for sale with a picture of the dash at tickover showing around 600rpm.
Check for engine mount wear or exhaust catching bodywork.
I believe tickover can be adjusted via T4 but you would have to check.
I stand to be corrected on this but I can only speak as I find
