I received the following information from Cornell Publications recently. I own seveeral G&H's myself, but have not tried this out yet.

Griffin & Howe, the custom gunmaker, was a division of Abercrombie from 1929 until Abercrombie bankrupted in 1976. It is now a private company, but in the vaults are scores of musty old ledgers dating from 1901 for VL&D and from 1929 for A&F, each containing the records of sale for thousands of firearms that passed over the counter at these two venerable firms. Bob Beach, the chief cook and bottle washer in charge of records research with G&H has meticulously overseen the laborious task of transcribing records to digital format that you can search and if you get a match for free or get a certificate for a nominal charge. The records G&H have are from VL&D from 1901 until A&F took them over in 1928 and for A&F from 1929 until 1976. To date he has added over 25,000 guns to the list from 1901 until 1939 with lots more to come- you have to keep going back to the G&H site to see new entries.