I am the gent who put together a dating guide for Gretsch. Based upon the information that I have gathered from over 5,300 drums, I am pretty confident that the serial number provides a good estimate of manufacture date. I acknowledge that not everyone agrees, but point out that not everyone has looked at it in as much detail as I have. I describe how I gathered and analyzed the data and present a chronology of changes in many different components of Gretsch drums from the early 1960s through the early 1980s. More information about my paper is available at www.gretschdrumdatingguide.com and on posts on this and one other drum-related forum.
I have turned my attention to improving the Ludwig serial number based dating guides which have been frustrating you, me and so many others. I have gathered information from almost 1000 drums which possessed both serial numbers and date stamps to augment the guides that are out there, three of which are available at www.vintagedrumguide.com. Those guides were not based upon nearly as many different data points. I have also created a dating guide for Ludwig Standards of the late 1960s-early 1970s time frame. Preliminary information about these projects is posted on my website under the Ludwig Serial Number Dating Projects tab. I am also working on identifying and dating the multiple variations of Gretsch round badges used from the 1930s through the late 1960s.
Note that no dating guide is going to be 100% accurate, as there are many variations introduced by the production and inventory procedures employed by the manufacturers. However, the guides do provide useful estimates. If you are looking for down-to-the-day precision, especialy on vintage Gretsch drums, I fear you will continue to be frustrated.
Be careful about the vintage drum curiosity bug. I caught it six years ago and have spent countless hours gathering information to create the guides that I mention above, my basement is full of drums and drum carcasses, and right now I have two dismantled snare drums on my kitchen counter awaiting reassembly after a thorough cleaning. It is addicting.
Regarding your drum, I see two different serial numbers in your post. It appears that one is missing a digit, but I can not be sure. Be mindful that the serial number is only a part of what one should consider when dating a drum. The other characteristics should also be consistent with drums in that serial number range. Also, one must understand how Gretsch reused serial numbers to be able to use them to date drums.
Rick