I have a GED from the 90's too. I guess I will find out if it matter soon. But I think good undergrad work should more than qualify anyone for law school admission. Perhaps having a GED will actually show that you overcome adversity to achieve your educational goals. It has to indicate some quality of your character since most GED recipients are from disadvantaged backgrounds.
I have a GED and I have been admitted to a top law school. I expect to be admitted to more of them over the next month or so. They might be curious about your scores, since the GED exam is standardized. If your LSAT score isn't that high, you may be able to say you have a history of poor exam scores...especially if you also did not do that well on the SAT/ACT.
Other than that, dropping out and getting a GED may support a contention of overcoming "hardship", but it's mostly irrelevant.