I would say your boot lettering is definitely wrong and not how delivered from the factory.
Here is my 1969 S4 (G registered, like yours, prior to export to California) as delivered to me at the factory:
Basically, the "T" is centered. Then the "O" and the "U" are spaced 5" to the left and right of the "T", centered on the license lights. Then, the "L" and "S" a further 5" to the left and the right.
Here are some measurements I made on spacing just before sending my car in for paint (still there). I insisted that the shop not fill the existing letter holes. Those holes have been maintained, which will make life much easier for refitting the letters later.
On a side note, the chrome on my original letters was rather pitted so I purchased replacement letters. While these look OK, I found them to be slightly smaller than the originals and also made of chromed plastic. Thus, I am having the original letters replated.