That is up to you to decide. Many have sent their knives in for them. I used to, but have grown to like the single better. On the small the 2nd thumb stud is not overly easy to use(at least on some knives), so you might be getting little benefit other than it looking balanced.Ok, so it's not worth sending it back to CRK for that. Thanks.
All,
I think I will send the knife to CRK and have the 2nd Thumb Lug installed for all of the reasons stated by photoman. Why shouldn't I have exactly what I want, right?
Thanks to "All" for our input.