There have been some additions to Daria48's Fake Serial Numbers post since I copied it here so maybe it's time to update our list
http://forums.ebay.com/db2/thread.jspa?threadID=2000179152&start=0
Here are the most common fake serial numbers found so far on the older bags, and some of the numbers are appearing on newer fakes too:
NT-4903
NT-4908
NT-4115
NT-4157
NT-9992
DK-8674
TF-6823
TN-4136
TN-4186
TN-9085
TN-9096
TN-9951
4C-8624
4C-9911
40-8624
7H-7456
ANY Coach bag with only two letters or one number and one letter to the left of the hyphen can be assumed to be fake.
Any serial number that has only one set of numbers after the "No-" is fake, such as "No-10325"
501-20 + all similar numbers starting with 101-, 202-, 501-, 701-, etc., followed by 2 or 3 numbers after the dash and usually with a patch that says "made in Korea" are fake.
Coach never made bags in Korea and never used serial numbers with only 5 digits like this:
"xxx-xx" or "xxx-xxx" and without the abbreviated "No." in front of the numbers
Coach never made "classic" leather bags with matching sewn-on cell phone holders.
H4B-0516
H4B-0678
H4B-0517
H4B-0520
H4B-0532
HRB-0516
Probably ANY serial number beginning with H4B followed by a style # beginning with 0 is probably fake (a Scooter Bag H4B-9893 and a Bucket Bag H4B-9948 are two of the exceptions)
012-3445
A2G-6094
A5B-3906 - fake Sonoma Double Zip Bags
J4D-4133 - Fake if it's NOT a Waverly Bag
M4N-4154
Anything starting with M4N is suspicious.
There is at least a 75 percent chance that bags with this number are fake:
308-9875
308-9937 - probably fake
There are some ending in
-9927 but aren't Willis Bag
Any recent or current model bag with a serial prefix of
M3U- is fake. A genuine bag with this number would have been made in 2003.
The counterfeiters also use many legitimate-looking serial numbers but on the wrong style bags or accessories, like
-5659 which should only be on a Scribble Tote, and
-1417 which should only be on an East-West Leather duffle. Accessories with style #
-5077 are fake, that number belongs to an Optic Bee Tote.
And there are fake Sonoma-style bags with
-4394, -4082 and -4398 style numbers
Recent Coaches with a
thick paper tag that says "Made In Italy" are fakes.
Check EVERY bag that you buy or sell carefully! Double-check the serial number against others listed for sale. And please report the fakes to Ebay.
And always ask here at the Authenticate This! thread
http://forum.purseblog.com/coach-shopping/authenticate-this-coach-21893.html
or at the Ebay Purses Forum if you're not sure
http://forums.ebay.com/db2/forum.jspa?forumID=1000000009