Ok, for once I get to post a solution. I actually found near perfect center cap replacements on ebay. They are one piece instead of two but made of solid polished stainless steel. The vendor usually sells them with rim covers , but was willing to sell what I needed for around $200. I got all four rear ten lug center caps, the two 5 lug front caps, and 50 1 1/16" lug caps as well. The lug holes were a little larger than what I have, but I turned the cap in either direction to take out the slack and it centered up fine.
The description listed on Ebay was for a "19.5" Chevy GMC P30 Dually Wheel Covers 10 lug rear 5 lug front new bolt on" and the seller was "the_hubcap_king" You may want to contact him before ordering to make sure he knows you don't want the rim covers.
Good Luck, Kenneth