Appears to be a 60's stamp Kevin. You can measure the height of the stamp. To be a 3 dot Large Stamp from the mid 50's it would need to be 1-7/8" or so. 1.25"-1.50" range would be 60's.

Thanks, Mike ...!!

Looks like the 1.5" tall version of the 60s stamp to me. My methods aren't 100% to tell all 1.5" 60s from 1.25" 60s unless you put a ruler next to it. But they are pretty good:

http://black.net.nz/avedis/avedis-gallery.html#60s-tall

The 50s version with 3 dots in a triangle is fairly easy to distinguish from the 60s. Here is how I do it:

http://black.net.nz/avedis/avedis-gallery.html#largedots

Very cool, I see the alignment of the N and E....

Thanks, All ... !!

Kev