Difficult to tell from the pics, but I don't think it was redone.
When trying to find a reblue job, you want to look for:
1. absence of wear
2. pitting, scratches, or dings UNDER the finish
3. SNs and writing that appear partially filled or faint
This one shows wear on the edges, the SN/writing appears sharp, and there are a few visible scratches. If it WAS redone it was a long time ago.
I'd say the first thing to do is ask the seller. Hopefully he will be up front if it was redone. I don't think it was, though.