That doesn't seem right though. The wing tips, cockpit and overall proportion do not match with a J20 model.The truck pics look more like J-20 parts than FC-31 parts.
If you notice, the FC-31 has very narrow tail connectors:
View attachment 70852
The F-35's tail connector also terminates before the full length of the tail:
I'd say this is more likely J-20 parts, not FC-31 parts.