ASG also offers a good service. I like how their encapsulation looks. They do to in case-by-case basis though so they'll probably do it just for the red stamp.
https://www.asgstamps.comThe physical stamps are all black though. How would they be able to tell the difference, without scanning it unless you asked specifically?
Disclaimer - I know zero about "graded stamps", sorry...
Yes that is a good question. I think they can do it two ways...
a) Grade and scan the stamp and say is is red digitally as well
b) Grade the stamp as is.
Kind of like our loaded coins...we have to look up the loading digital value of the coin.