This is the one I ordered. Numbers are my today's legal plate, not the plate itself.
You can put a sticker on the right top corner, supplied by them as well.
Your selection may very well suite your purposes I imagine, however in the actual usage of characters by the California DMV while using the black & gold plates on passenger cars (such as your 67 Mustang), there would typically only have been three letters followed by three numbers. (example ABC123), a total of ONLY 6 characters used.
Later, when personalized plates became available (maybe somebody knows what time these plates became available, I do not), you could only use up to 7 characters and one half space. When I ordered a set of official (legal) personalized California license plates in 1984 for my 67 GTA, I was explained then the limits set up by the state. The list of choices or ideas I had come to the office with as options (I had 4 of them I recall, I wanted the year of my car, GT or GTA in some order or another, so people might quit asking me "What year is your Mustang?), all of the ideas I had were already taken at the time by somebody else. I found this out by looking through the "unavailable" catalog before filling out my application. I finally found one that wasn't taken and I purchased a set of the, then available "Sunset" plates with 67GT4ME. I still have those plates and they are in good to very good condition. Very much like your idea though, I ordered a set of reproduction plates in Black & Gold with the same characters previously used on my "street legal" personalized plates. Since these reproductions are for show purposes only, I do not intend to drive on them.
Keep in mind, license plates of any kind are not exactly "concours" in the state of California. New car owners left the dealership with a little piece of paper in the right front corner of the windshield, indicating to any police officer that the paperwork had been submitted (by the dealership) to the state. The plates arrived later.