The book was printed in Livorno, as were many North African and Italian books of the time. It featured three different sets of haskamos, by Italian, Tunisian and Moroccan rabbis, for those three respective book markets. The approbations in the Italian version were written by R. Isaac Samuel Reggio (Yashar) of Gorizia, R. Mordecai Samuel Ghirondi of Padua, and Shadal. In his introduction, Ashkenazi singles out Yashar and Shadal for their publications of never-published material; Yashar having published the shorter Ibn Ezra commentary to Exodus, and Shadal having published the Divan of R. Yehuda Ha-levi.
You can see there was a mutual hotzi la-or appreciation society of sorts. Since printing was invented, it took some time for it to become widespread enough and cheap enough. The result being that many works in earlier centuries fell behind, having never been printed. These manuscripts lay all over the Jewish world, in private libraries, in genizot, in the hands of people who know what they were, in the hands of people who had no idea. So it was that in the 19th century there was an explosion of acquiring and printing these manuscripts for the first time, which has never abated.
Shadal's haskamah is very interesting because it contains his attitude toward uncovering and printing these old works. He believed they are like a gift from God, who is providentially ensuring that the present generation receives Torah instruction from the earlier generations.
He begins by praising God for the depth of his wisdom. God sees how topsy-turvy the present (=mid-19th century) is and he acts for the good of his creation, knowing that each generation needs its teachers and judges. To understand how God acts, think of a king who rules over a vast empire. When he sees that his subjects in the farthest reaches lack proper supervision, he sends them leaders and judges from other provinces. So it is that God saw that the generation is orphaned, with many following nothing and nonsense. Even the sages and wise men are ineffective as leaders. So what does God do? He sends them sages and leaders from another generation. He causes old books to be lifted out of the dust piles, in order that their voices can be heard in a later generation. It is as if he returns the soul to the dead, breathing new life into the hearts of those that are straying. He turns the heart of the fathers - already dead - to the children, in order to turn the heart of the children toward their fathers. This is just in time before it's too late and the generation all goes to waste. This is divine providence, good medicine for the present generation, which is a vain one, a generation which forgot Zion, and is pining for Emancipation (check out that font size). Then he refers to his own publication of R. Yehuda Ha-levi's poems which are full of love for Torah (and Zion, although he does not mention this). Those poems were a big hit, with people even translating them to the vernacular. Thus, good teachings from the past are spreading among the Jews, to counter the bad tendencies of the age.
He then praises the present work, R. Abraham Halevi Bakrat's Sefer Ha-zikaron, for his commentary on Rashi ("Rosh Shivtei Yisrael," - Ghirondi calls Rashi "Hamelech Shlomo Yitzchaki" in his haskamah),which was written in clear language, with straight reasoning, manifesting a love for the truth, pursuing the peshat, eschewing pilpul, showing his expertise in all areas of Hebrew grammar, as well as Aramaic, Arabic, and Mishnaic Hebrew. He also enumerates various other qualities of this commentary, such as explaining matters through textual criticism of the Targum, supplying an example or two for each one. Can you imagine? A haskmah which actually shows that the muskam read it, and even tells the reader were some of the good material is to be found! Finally, he closes by assuring everyone who purchases this book and reads it that they will not regret it!
(This letter is also printed in Penine Shadal (Przemsyl 1888) pp. 47-49. Monford Harris quoted a little bit of it in his article "The Theologico- Historical Thinking of Samuel David Luzzatto," JQR 52 (1961-62), but the entire letter needs to be seen for its full context. My thanks to Leor Jacobi who copied the letter for me from Penine Shadal - which seems to be the only important Shadal source which is not yet digitized. Harris gave no indication of where the letter originally appeared, but Penine Shadal told me where to find the haskamah itself. Without knowing where it was originally printed, and the attitude of the publisher himself, much important context would be missing.)