It is not like it costs an arm and a leg, but it may be just a matter of principle. What if along with you shiny certificate of registration, you could also get your stamp? A nice way to say thank you and congratulations you made it this far, your state recognizes you as a registered professional.
The upside is that I can now choose my own seal stamp, as fancy or cheap as I want it to be. If you are looking for one, google architect seal stamps. Just be sure to follow your state's seal requirements. And if you recently got registered, congratulations to you!!