Numbers (and pointers) in the x86 are stored in "little endian" format. That means that the least significant byte is stored first. If you're looking for a pointer whose numeric value is 0x12345678, then you want to look for the bytes 0x78, 0x56, 0x34, 0x12 in memory (in that order). Although not certain, I suspect that the same format extends to 64 bit pointers.
Another possible thing to look for is relocation. When a program is loaded into memory to run, the operating system adjusts pointers in the program image to match the location where the program is loaded. This may or may not be an issue, depending on your operating system.