I just bought a 1993 Z28 police package camaro. There is a metalic tick that is coming from the 3 or 4th cylinder. After investigating lifters, rocker arms and springs I still have no idea what the problem is. The car has never ran out of oil and the tick sounds like it is coming from the top if you are on the top and sounds like its coming from the bottom if you are on the bottom. Much confusion coming from a seemingly simple noise under normal circumstances.

Start by removing the fan belt(s) and running the engine briefly. This will eliminate accessories as possible culprit. Obviously, if noise stops, then it is an accessory.

If noise still continues, then put belt back on and get yourself a "mechanics stethoscope" or something similar. Actually, I have used an old broom handle for decades and it works OK. Just hold one end of the handle to your ear and then move the other end around on the engine and you should be able to localize the area the noise is coming from.

Metal is a excellent conductor of sound, so it is easy to be fooled about the location of the ticking. You gotta listen closely.

Could be flywheel hitting dust cover or lifter as you suggest or something else. Good lifter/rocker/spring test is to remove valve cover on suspect side, run engine and carefully push down on each rocker with bunched up rag as engine runs. If you have a loose lifter/rocker/spring, this will quiet it.... thus telling you to replace that one

Probably an injector. I had a 93 and the injectors got loud in the spring when I took it out for the first couple rips. Definitely sounded like a lifter though.
Have you tried a stethescope or a long screw driver? You can isolate the noice easier that way.

An exhaust leak will make a ticking sound and will leave an ever-so-slight black soot around the leak if anything at all. I've got a $20 dial gauge I use to check lifters. If one is wore out you'll see several thousands of an inch difference in it. I also have been know to borrow my son's $10 super-sonic ear (amplifier and phones) to chase down a sound. I've also used the hose and funnel as well as stick / screwdriver tricks as well. Taking the belt off will reduce the noise substantially.

Another thing to check for is a loose spark plug.