No.  We generally only record evidence of title in the United States.  No change needs to be made to existing deeds, and "acres" are always the least important information in the description on those deeds in any case, often "more or less" in legalese.
In fact, especially in most of the western United States, the normal descriptions in deeds are government sections, quarter sections, quarter-quarter sections and the like, and all across the country in towns block and lot description.  They aren't usually done in metes and bounds.
Generally, there are at least 11 sections in every survey township which contain more or less than 640 acres.
The boundaries wouldn't be redrawn; the country wouldn't be resurveyed in one-kilometer blocks.
Parts of the U.S. have already made similar changes from arpents or varas.