You're probably not going to be able to use that bit for bit copy later.
I did something similar with my last linux laptop, and none of the workarounds to put the partitions back worked when I needed a quick windows test machine.
Actually I did the same with My wife's Asus, I dd-ed the whole drive, gzipped it and ran Linux for a year. Then I restored it. It worked fine. I guess I won't run into problems as long as the drive is the same drive, or perhaps a bigger one.
