Well at least not that much. You remember how Marty said that he could go back in time and save Doc before he got caught? But then Doc said that then that might result in the Delorean not going back to 1986 and telling Marty to go back for Doc and it would "end the universe as we know it". Well why couldn't Marty go back and rescue Doc and go back to 1986 without using the Delorean that Doc used to go to 1931? What I mean, if Marty went back to the time the speakeasy burned down, there would be two Deloreans. He just wouldn't have to use the one Doc used to go to 1931, but instead use the one that brought him (Marty) to 1931! Isn't that a brilliant idea!
Now he doesn't need to subpeona his grandfather or drive a rocket powered bike or steal a hat full of peanuts!