yes, there is a holder that you attach the plate onto that then screws into the holding "blocks" that are already on your car.
(no affiliation)
here's one:
http://www.pcars.com/porsche_parts/shop.php/porsche/boxster-/-s-986-/miscellaneous/license-plate-bracket-kit/p_2074.html
another option is to use a tow-hook mount that simply screws into the tow hook screw and doesn't require any changes to the front of the car.
(again no affiliation)
http://www.schattenbaum.org/TechArticles/FrontLicensePlateMountUsingTowHook.aspx
of course, you could always do what the PO did to my car, just drill holes into the bumper and screw the plate directly onto it...
i prefer no plate anyway so i just took it off and filled in the holes with the bumper plugs.