What's the problem???? You post a question, then wait 3 hours for an answer before complaining, then wait another four hours before doing it again, then wait a whole 24 hours before giving up.
Sorry, but I don't have a ton of time each and every day to hang around the boards. If you need an immediate answer to a question, a discussion board isn't the place to get it. My phone number is (763)261-5600, and my e-mail is firstname.lastname@example.org. E-mail is answered once a day.
I'm sorry, man, I usually don't respond this way, but come on...
In regards to your question, I don't offer pinned comps as an option in any form. From what I have been able to gather regarding the group buy rifle, I don't have anything similar.
I wouldn't recommend switching bolts back and forth between uppers in any situation.