When you remove the flywheel, make a couple scratch marks on it and the crank so you can be sure to put it back the way it came out. I don't think there are any balancing weight considerations, but 'just because' is a good enough reason to me.
I kinda still think the pump is going to be found good, I may be wrong, and I would obviously check the pickup screen before removing the pump. If you do replace the pump, take a look at the main and rod bearing inserts. You can just remove the individual caps, clean and dry the journal and bearing, and use some Plastigage to check the clearance in-vehicle. If the inserts look worn, for a few dollars you can replace with the proper size if they are marked .010 or .020, etc. You can also (well, could) buy slightly undersized inserts from FoMoCo to get the bearing clearance correct without grinding the crank. They would be in the .00010 and .00015 area of diameter smaller than factory. Using them, you can close up the gap if yours are a bit too loose. I don't think mains are available that way.
tom