That damage you show in that picture is pretty common, I have seen plenty of one piece countergears with the same failure. I think the 2 piece countergears went away due to production costs, I haven't yet seen one that has tore the keyway or key FWIW. When I see that happen then I would be afraid of them, but they are fine for gas motors. I see they still make that 38T front gear for the early style countergear with a 22T input, some parts aren't available from one vendor to the next for various reasons. I would assume these are slow moving parts especially for the early chevy with the 20T input, those are very uncommon.
My chevy built into a dodge diesel NV4500 has a one piece countergear, I think NVG used it across the board in 95-96. When the reverse ratio changed in 97 they were only offered as a one piece countergear.