A. It would be presumptuous for me to claim to be an expert
B. I suspect the simpler vent (a loose fitting cap pinned onto the vent tube) was a case of simplify to cut production time and cost while maintaining most (some?) of the dirt protection capacity of the damaged version you have
C. It is possible to use the vent caps sold for Chevrolet 235 CID valve covers to fabricate a passable replacement for the damaged transfer case vent. My process is: uncrimp the perimeter of the damaged dome to remove the perforated flat panel (and the filter medium if possible), braze/weld/solder the recovered flat panel to the recovered (or a new replacement) pipe that threads into the transfer case, reinstall the filter medium into the dome and crimp the edge onto the flat disc. If the filter medium isn't recoverable, consider usiing metal mesh from a pot scrubber (also sold as pest control
https://www.leevalley.com/en-ca/shop...copper-blocker).