Are you sure they added to it? Even if you got more shares they might be a diluted percentage. "I'm not sure" often means "I've already been screwed and I'm not yet aware of it"... I hope not in your case, but if you don't know the numbers, don't take for granted that they are in your favor (this is the sort of thing you learn from painful experience).
Also be aware that (assuming you have investors) the deal might be structured so that the investors get their money back and your stock options are worthless. Getting a high salary in the acquihire job offer might be your best option.
