Metal in the oil is usually a bearing going bad, that with your bad oil pressure sensor, or worst case, zero oil pressure, sounds really bad.
I'm trying to think of anything that could have gone wrong with an HCI swap, but a bad cam bearing probably isn't it because you used the assembly lube.
Could it be your oil pump drive shaft?
Could your distributor gear be disintegrating?
Did you let a bunch of trash fall in to the lifter valley during the swap?
What happened that made your swap cost $3,000?
Did you notch your pistons in the block?
I wouldn't drive it untill you show the oil to a good mechanic, or fix your oil pressure gauge and confirm that you have pressure.
I hope it's just a bad gauge and some residue from the swap. Good luck any way.