Don't need a cam in it to leak it down.

For what you're looking to determine....if the valves are tweaked or not......it doesn't even need to be at tdc. Just hook up the tester and pump some air in and see what the leak % is. If it's pretty high, see of it's blowing by the valves.
The air will push the pistons down if you're not at tdc, but it won't really matter for this test(with the valvetrain not functioning).