I found one - 17423. Now this came with a matching frame/engine machine 223** from contract C/S 1546. I need to pull another tank out, but I know that that came with a post-war CO, so I'd be surprised if it has a number. Another (with traces of army green evidence) has none. Another tank I have just noticed has a cutout under the tank on both sides of the central saddle. Any idea what it's off?