Oh yeah, I know that. That's what I'm saying though. Our Thousand Sons and Noise Marines are just resin upgrade kits, and our Plague Marines are off-scale full resin, and our Havocs are all resin for all our heavy weapons except the Heavy Bolter.
Your Valhallan or whatever.. they don't matter in the grand scheme of things. You can use Cadian and Catachan models to make a full plastic force without losing any codex entries, except maybe Ratlings or Rough Riders.