Thanks for the response theducks, but what I did actually had the intended effect. My custom column is actually just displaying the identifier, actually.
Basically I had an "amazon" identifier that I wanted to copy as the "mobi-asin" identifier as well. It worked
Now I just wish there were some tool to download mobi-asin's
I'm not sure if the Amazon IDs are the same as the MOBI ASINs, I think the MOBI ASINs begin with the letter B.