I believe there should be a consideration as to who's chokes are installed. Being the owner of a double with Teauge's "invisible" flush chokes installed, I can attest to his work being in a league of it's own.

Without knowing they are installed, you would miss them at a glance. The gun is also re-proofed after installation which helps in a world wide market if that is a consideration.

Yes, I agree that having chokes installed in a high end gun will affect it's value. However, I believe that hit in price is a sliding scale depending on who has performed the work.

“I left long before daylight, alone but not lonely.”~Gordon Macquarrie