Hopefully you are looking for them BEFORE the tear down. You can always make your own marks.
The original marks are viewed from the top and are on the inside edge of the gears. Crank has to be at an odd spot not at TDC like one would normally think. The one on the inside edge of the crank gear can be tough to find sometimes. I think they are usually near hidden by the crank throw for # 1 rod.