rear valve cover gasket leak on 1995 Lexus ES300

there seems to a slight fluid leak under the hood.The service mechanic says my rear valve cover gasket is leaking. your repair directory talks only about valve cover gasket replacement(right and left side).Could you please tell me which side(right or left)is rear valve cover gasket. Thanks. my e-mail is

Asked by for the 1995 Lexus ES300
The right valve cover gasket is the rear about 2.5 hours to replace the rear gasket and seals plus parts. Check the valve clearance while you are there they are shim adjusted.
What is the going rate for a mechanic to change both valve gaskets?