There is an interesting issue here. Prof. Israel Finkelstein has noticed in his work the lack of pig bones in Israel.. (Northern Kingdom) But this article points down to Judah. I think you will find the Egyptians also didn't eat pigs. (I might be wrong about that I just remember reading it somewhere)
Judah in 700 BCE was actually a brand new kingdom after the fall of the Northern Kingdom of Israel. Not only that they intermarried with the Assyrian rulers thus adapted their customs. (It is likely Hezekiah and Sennacherib were first cousins.)
As for the law against pork in Leviticus 11 and Deuteronomy 13 I actually would date them to the second century BCE after the overthrow of the Seleucids whose diet rich in pork was offensive to the now reigning Hasmoneans. (According to 2 Maccabees chapter 6 a man was forced to eat pork by having it forced down his throat and being beaten to death.)