Yah, I was able to manually verify it, but was just noting a possible problem in FireGPG.

Thanks the_glu ... this is still an excellent application!

It seems that if an incoming message is in reply to another .. so Gmail detects this and provides a way to "show" or "hide" the "quoted" text, verification of a signature fails.  A screenshot is below ... I've copied the "raw" message into "gpg -v" and it verifies correctly:

As you can see, this message includes "quoted" text that the author included in the signed portion of the message:

http://pics.adml.us/d/38005-2/firegpgproblem.png

I am not entirely sure of the problem, but I assume FireGPG might need to detect this, expand the message, and run "gpg -v" on the entire message.