I think you are correct. If you look closely at the subpoena from Issa to the DoJ, it is limited to a very narrow window of time.
It was clear to me that Issa knows exactly what happened, and when. He is only looking for the document trail to ensnare the guilty.
Issa knows this only because the ATF permanent bureaucracy has turned on the appointees and the folks they've promoted since Obama came to office.
You know there are undoubtedly contract proposals to purchase tracking devices for the stocks on the long guns. Somebody refused to sign them ~ too much money ~ nothing in the budget ~ hey Democrat big dogs when Congress doesn't approve a budget, the agencies don't have any line items to charge NEW STUFF against. Continuing resolutions just don't let you keep up with technology or buy enough tracking devices.