Nope, the only reason to drop the pan is if you replace the timing chain. Then you drop the pan, unbolt the oil pump, pull the timing gear and reverse for installation. Not worth it unless your pump is dead. When replacing the oil pump you have to get it aligned properly or it will not last any time at all. Some guys get lucky and it falls right in place but there is a special GM tool to align it properly. Books tell you that you can take the pump cover off, put a .002" shim between the pump rotor and the pump body bore and then tighten it to the block. I do that and check all around the rotor for the .002" clearance after tightening.
BTW, the only reason for dropping the pan in the above sequence is to gain access to the bolt that holds the oil pickup tube to the pump. Replace the pickup tube seal when replacing a pump and be careful to install it correctly or you'll have real problems. Put the seal on the pickup tube and then install the pump to prevent damage.
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