Cachet On Front And Back Of Cover

The FDOI of this C27 is actually 3/15/41, not 8/1/47. My question relates to the two different cachets. Does having two cachets enhance this cover to a cachet collector, which I presume would mean a slightly increased value?

Not a C27 FDC but rather a F.A.M. (FAM 33) cover.
Don

As Don has documented, that is a "First Flight Cover," not an FDC. I don't specialize in first flight covers, but it is unusual for them to have a printed cachet like that. What you usally see is the rubber stamp cachet that you have on the back of the cover on the front left of the cover. That printed cachet is rather generic, but it does make for a somewhat unusual example. Recent sold covers on ebay with the rubber stamp cachet went for $0.63 to $1.65 (plus shipping). You might get a bit more for this one, I suppose, but even 100% more would only be in the $2-$4 range.

Instead of asking for values, you might consider learning how to search ebay to find covers similar to the ones that you are interested in, and then select the "sold" option (one of the many options at the left, if you scroll down far enough) to see what similar covers sold for.