Union City, Ga, T-209 On 1918 6c Airmail

I just came across a Union City GA C1-209 and looked it up in my Brunell -- it says the precancel is down ("6d"), but mine is horizontal, which he would indicate just as "6" since it's a horizontal stamp. Right?

I'm thinking this is probably just a typo in Brunell and he really meant to put "6"? [easy mistake to make because so many other towns do have the precancel "down" on a C1 and it's a horizontal stamp]

Or maybe both the horiz. and the down are in fact well-known for Union City and he just missed listing the "6"?

Then again, maybe I really do have the only one ...

Thanks.

This is the 6dn, if it doesn't look like this, it is something special :)

Really?

How would I find out more -- like whether it's just a fairly-common stamp omitted by accident? [Edit: Or a fake????]

[Edit: Pity the plane isn't upside down, too.]

99.9 sure it is not a fake. I would email BruceB with the scan, using the address in the book - and ask.