Official Series Of 1941

I came across these document stamps, series of 1941, however they are hand dated 1939. I have the full document and all the dates match (July 20, 1939) with the writing on the stamps. I don't know much about the Revenue stamps, and the Scotts Specialized does not list dates of issue. So, is it unusual or unique to be cancelled two years prior to the overprint series date? Or fairly common?

The document and the stamps were backdated for some reason.

Backdating has legal implications, doesn't it?

It would be nice to see the full document to see what kind of transaction was involved. Backdating is not common, but in my experience this occurs with private transactions and then when they get around to filing the document in a courthouse they need to be sure that the tax on the transaction has been paid. So they get the current tax stamps and date cancel them with the effective date of the transaction.

By the way the Series of 1941 were not issued until January 1, 1941 and were valid only during 1941 and 1942. After December 31, 1942 they were demonetized, although we occasionally see them used after that date. This is especially true for the dated silver tax stamps.

Here are full scans of front and back. The notary dated her signature as 20 July, 1939. If it were a backdated document, shouldn't the notary reflect the date it was actually signed? One thing that would point to backdating is the filing date on the front stamp, it was filed 17 January 1942. It seems to me if it were backdated, there would be some other indication of when it was actually executed.

Well, of course the stamps were backdated. The deed was not filed until 1942, when the Series of 1941 stamps would have been available. The reason for backdating is to pretend that the federal tax had been paid at the time that the transaction took place. The deed could not be filed without showing that the federal tax had been paid. The Series of 1941 stamps were not available in 1939.