I recall noticing that there were still sections of granite curb remaining up into the 1980s and 90s. Can't remember exactly where, but Upper Water Street comes to mind. That's pretty good service life given that much of it was installed in the late 1800s. I recall most of it had settled and the sections didn't always line up very well by that point.
As far as finish goes, I think it was somewhat rough cut, given that it was just curb, and wouldn't justify the expense of bringing the finish up to polished level. If you browse through the
Rogers' Photographic Advertising Album on the NS Archives site, you can see several examples of curbing that looks quite rough even when it would have been relatively new.
As far as SGR goes, it would be nice to see rough granite or even sandstone rather than bare concrete, but what is there is fine.