Flag And Statue Of Liberty

I have a Collins book from USPS to try and sort my stamps out. In it is numbers 3979 and 3980.
Both of these stamps are listed as coil,serpentine die-cut 11 vertically.
The only difference I can see in the book are the dates
of 03/08/06 and 01/09/06
Now the question I have is how can I tell what I have?
I have a couple of stamps that are to me the sane. What difference if any should I be looking for.
Any help would be appreciated.
I have missed all my friends here, hope you are well.

Bandicoot Hi,

3979 is perf 10 and 3980 is perf 11.

If you find a spare copy of the latter, used, I would love to exchange. Thanks.

Hope this helps

Londonbus1....Flags galore

Hi Bandicoot,

Here's a little more info from the PNC3.org website:

The 3979 has water activated gum (lick and stick) and was printed by Sennett Security Products.
http://www.pnc3.org/Data/LadyLibert...y-39-SSP.htm


The 3980 is self-adhesive and was printed by Avery Dennison.
http://www.pnc3.org/Data/LadyLibert...y-39-AVD.htm


Dave N.
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Thanks Oldtriguy, that makes sense as the book has them both listed as perf 11.
And I will check on the extra 3980 for you Londonbus1.