Poss. 504B

Gracie, anything could possibly be a 504b, but why do you think this one is? And what is a 504b?

Peter

Peter...Isn't a 504b a double impression..?

Robert

no it isnt, a 504b is a double impession and would have no white inside the right frame line

Gracie,
Give this a read to learn about plate and inking varieties: http://www.re-entries.com/terms.html

The varieties are often difficult to distinguish. Asking for clarification is perfectly understandable. Also, it is very helpful for us to understand your reasoning for what you suspect so we can best help you.

I agree with the others that your stamp is not a double impression. Every stamp has minor inconsistencies in printing. Focusing on them is usually futile. Identifiable patterns amongst multiple stamps is what matters. Your stamp seems to have been printed from a plate that had a build up of dried ink that resulted in an uninked area of the top frame line above the "ST" in POSTAGE.

gracie1125, keep posting--Keep asking. We're here to help you in your learning curve. AND, sooner or later you'll find treasure out there--we all have at some point in the years of "hunting".