Keep both bikes! If you’re not hurting for money, having the backup will be worth more to you than whatever cash you’d get.

If you had 5 or 6 bikes with a lot if overlap and an overcrowded garage, I’d say you should get rid of at least one. Two bikes is never excessive.

The only other situation where I’d vote for selling is when you never ride one of the bikes, and you need some cool new wheels or something for the other one, with no funds available.

In your case, I doubt you’ll ever regret keeping two. If you sell one, there’s a good chance you’ll come to regret it.