I was asked this question when I was at my GW store. I had no idea, I guess it was possible but unlikely? They basically look like Sanganius
The big thing about the Astartes is, though, when they get called in, everything has gone, or is about to go to, shit.Considering the Adeptus Astares are already considered, "The Emperor's Angels" of death or whatever, I imagine that Sainthood would be a downgrade.
As well, I would think that any Astares isn't going to be involved long enough with civilians to get a good enduring impression, outside of, "wow, those guys showed up and everything got destroyed."