As an artist and retired visual art professor, I'm updating my master thesis written in 1997 as a hand-crafted art book. Today I'm self-publishing a rewritten thesis as a paperback book to include more of my artwork since graduating in 1997 with my master's degree. Is it legally okay for me to use the same Acknowledgement Page in my current self-publishing book with the same title as my master's thesis, or drop it completely?
If you wrote the original Acknowledgement page, and you still feel the same way about the help you acknowledged, then I believe that it is perfectly appropriate to use the same text. You are re-expressing sentiments that you had in 1997, using your own words. It is perfectly ethical to use them.
Beyond that, though, this would be a great opportunity to update the acknowledgements. "When I first developed the work in this volume, I was indebted to the following people ... ¶ Since then I have further benefited from ..."
Your decision to publish now, was it informed by your professional experience? Has your initial vision evolved since then, thanks to a stimulating work environment? Did anyone encourage you particularly to publish the manuscript?
If there are no copyright issues then the only other reason not to do it would be to avoid a charge of self plagiarism from somewhere. For research publications it is an important issue, since scholars want to see the complete context of a work to place it both historically and scientifically. But for an art publication, I doubt that consideration is as important. Except, perhaps, to art historians.
But as long as you say somewhere in the new publication that you are updating or "have taken material from" the earlier thesis, citing it, then you have fulfilled their needs.
But it would be pretty simple, perhaps, to title the page "Acknowledgements (1997)" to make it crystal clear. I recognize that artistic considerations are very important here, of course.
Of course, if the copyright to the original was given up to another party, then you need to deal with that issue directly.