There was a back and forth discussion about this not long ago. I believe it was determined that in the eyes of the TPG's, chop marks are damage. Among the folks that discussed the issue before it was a fairly even spread. I happen to reside on the other side of the road. I appreciate the history that chop marks speak to me. It's one of those things that's rather like toned coins. Either you love em or you hate em. One of the reasons coin collecting is so great. You can't do it wrong!
They are considered damage, but I'm with @Randy Abercrombie . Here's my only example of a Trade Dollar:
Not sure why not. This 1 in your post above was probably slabbed PCGS to get it authenticated. I think there might be many fakes out these from China so be careful if and when you buy them.
pcgs grades chopmarked trade dollars "straight" unless they show other damage, like drill marks, filing, or corrosion for instance. NGC routinely assigns a details grade, it's just their policy. I think the PCGS approach makes more sense.
It’s my only Trade Dollar and I love this coin. I envision it floating through Chinese market places.