Yeah that's true; to check the cam timing, the cover can stay on. I guess I jumped ahead a tad far just there.
Also for a quick-check, you don't need a dial indicator either.......you just need to find split overlap at or near TDC/exhaust stroke. If it's within 4 or 5 degrees,either way, the timing is good enough to not cause these kinds of problems.And,although I've never tried it, I believe that it could be done by just removing a valvecover.You would, however, have to make a tool.