I don't think that's a good bet, and it's an odd one if you agree with the first paragraph. You don't give a reason other than age (how old is the bike?) for the bent hanger, and don't explain how it would be more likely than a friction issue.

A bent hanger tends to give the same problem in the same gear combinations. If the hanger had been bent inward, which is the most common occurence, someone would have had to know how to readjust both limit screws and the cable tension (to get the bike to shift OK after the hanger was bent) but not know enough to see a bent hanger, as the two extremes work fine and the shifting is mostly OK, just inconsistent.

The OP may not have given us all the info, but I believe his complaint is "sometimes" getting bad shifts to the smaller cogs. That is a classic friction/binding symptom.