Could anyone tell me how do distinguish if my engine is a magnum 5.2L? Please

 

How to tell if it's a 5.2/318 = Look on the driver's side of the block for a casting number, should see a 318 there (unless they moved it on the Magnums)

How to tell if it's a magnum = does your intake manifold resemble a small beer keg on its side? Do you have 2 fuel rails and 8 injectors? If yes, then yes it's a magnum.

 

Yes it has the beer barrel manifold but i've seen the magnum with valve covers that sayMopar Magnum like these are they add ons.

 

Yeah, stock magnum valve covers are boring stamped steel iirc.