I didn't say the wrong date is the end of the world, but one would think that savvy business peeps, could at least get the right date on a legal document NO.
I think the real point is that the wrong date on something as important as selling a company would imply that nobody carefully read it or the error would have been corrected.
The fact that such an error exists calls into doubt its authenticity ( in addition to other obvious happenings) since it is of great importance and several eyes (including paid attornies) should have read it very carefully.