It sounds like you are facing some technical challenges with your Chevrolet GMT400 K3500 Extended Cab mod. Losing the original working version can be frustrating, but don't worry, you can work through the issues you are facing with some troubleshooting.
For the body color configuration, bumper options, color configurations, and engine configurations, make sure each option is correctly set up in the mod files. Double-check to ensure that all file paths are accurate and that the configurations are correctly linked in your modding software.
Regarding the missing elements like the rim color, rear bumper, and attachers, these could be due to various reasons such as incorrect file paths, missing asset references, or errors in the mod configurations. Inspect the coding for these elements carefully to identify any discrepancies and correct them accordingly.
If you are having trouble pinpointing the specific cause of these issues, consider reaching out to the modding community for assistance. Forums, Discord servers, or modding communities dedicated to FS25 can be valuable resources where you can seek advice and troubleshooting tips from experienced modders.
Remember to stay patient and methodical in your approach to troubleshooting. By carefully reviewing your mod files, addressing potential errors, and seeking help when needed, you can overcome these challenges and bring your Chevrolet GMT400 K3500 Extended Cab mod to a fully functional and polished state.