What could we do on my husband’s felony charge because of the guns that he keeps for his hobby?

My husband builds semi auto rifles and preserves shotguns as well as other guns as a hobby. Someone claimed there are automatic weapons in our home so the Bureau of Alcohol, Tobacco, Firearms and Explosives came in said that his rifle that was in progress needed to be tested along with a few others. We had three riffles, one shotgun, a pistol, a couple barrels and a stock taken along with my husband who was taken to the courthouse and given an appearance ticket. We were given a list that they were hand writing as they took each item from the safe, we then received a receipt that showed what was checked in and was all correct with the serial numbers and types of guns. They were all logged as they came out and some were taken. They were then checked in to the county as evidence and showed exactly the type of gun etc. Funny thing we also received a receipt from the forensic lab that showed the same serial numbers but the guns were no longer intact. The person who took possession of the guns continued making comments about how easy they were to change to auto and honestly trying to irritate my husband knowing that my husband has no interest in automatic weapons. So forensics came back and claimed of those semi auto's that was in the process of being built was missing a spring therefore depending on how it was shot if it was held in the air it would shoot with repetition. My husband was then charged with a felony. He plead out because there was no fighting that and then we noticed that forensics shows that the shotguns that left our home were now rifles and parts were mixed up all over and the gun that originally left half built was now complete as an automatic weapon. Do we have any legal rights or should we just let things be?