I would strongly suggest that you review this with a local attorney. Your diversion program will protect your record but the charges will still be listed until it is expunged. Every state has a time period within which you must wait in order to expunge a record. you need to know that time period. good luck.
Read the terms of your PTD program contract. It will state how long you must wait after completing the program before filing in civil district court to expunge your record. Generally the requirement is at least 2 years, and sometimes as long as the statute of limitations.
If you are applying for PTD, then you have a lawyer. Ask your lawyer these questions - that is what you have paid him or her for is their advice and information.
Possession and ownership of the weapon can be two different things. You can not own the weapon even though you possess it even if temporarily. If you never possessed it, then go to trial.