According to research by the Zarahemla Research Foundation, the first occurrence of the name for the son of Com is spelled "Shiblon" (Ether 1:12) in the Printers Manuscript. However, the six references to the son of Com found in Ether 11:4-9 are all spelled "Shiblom." [Zarahemla Research Foundation, A Comparison of the Manuscripts and Editions of the Book of Mormon, p. 269]
Note* Because the name Shiblom ends with the letter "m," it might be more characteristic of Jaredite names. This practice of ending names with "m" is called "mimmation," and has been commented on by Hugh Nibley. [Alan C. Miner, Personal Notes]