Hopefully he will see this and let me know! I don't believe it is part of the book, from my investigating, I noticed the small pen trenches–grooves, within the middle of the thickness of the ink. I am sure it has been applied with ink, just not familiar with Mr. Lucas' autograph.
I hope you are right! In negative, it looks dead, same as the type ink, and has no cross over I can detect and those "dots"/stops/starts. But, it s just a photo.
Unfortunately, I was able to find a copy of the book online with the same signature that is printed. I'm sorry to be the bearer of bad news but you can see it on Google Books Here
This later edition of the book was published in 1996 or 1997, so the signature while a facsimile of Georges late 1990's autograph is not from 1976 and not an ink autograph. It is just a part of the introduction reproduced in the book.