I don't think those will work... those seem to be lights that can be used as running/brake/sig lights, not accent illuminating lights (i.e., put light on the plate/numbers itself). You need something like this or just search eBay for "license plate LED" -- I'm sure you'll find some that are cheaper. Also, these lights will act as illuminator and running/brake lights (additional safety feature), but you can get them without the red light so they can be just a plain plate lights. Another website I would recommend is oznium.com (great LEDs and very bright + super easy to install). You could get 2.4" white strip and mod them to the plate...L.E.D. bolts are just the thing.
A little ugly/bulky, but this is the general idea:
Curious, does your state issue reflectorized plates? California plates (except for old ones...) are reflectorized and light up as soon as light hits them. I'm sure there's some part of the vehicle code that requires licence plate lights, but I've never heard of anyone getting a fix-it ticket for this. Also, we don't have vehicle inspections (other than smog checks) so it's be up to 'The Man' to catch this.