If you do not follow up on that telephonic direction, you could miss your chance. Nothing to lose by you being there as suggested,

10th Group can’t snag you, contrary to popular belief they do not have requisitioning authority and they do not have their own special rules either. SF Group is just another Airborne assignment for E6 and below and the slots are filled by your Branch Manager. You can call your branch and ask them if they can send you to an airborne assignment, but 99% of the time once you’re on assignment their response will be that if they needed you somewhere else that’s where they would have placed you. However, most Skill level 1 branch managers need Airborne volunteers and it doesn’t hurt to ask.

What you don’t want to do is waste your opportunity by waiting and trying to report to the Group. Having worked in an SF Group for several years I can’t tell you how many times I’ve seen a waste their time holding out for an assignment because a well intentioned SGM or NCOIC told them they would get them an assignment somewhere. They didn’t take action in time and the Army picked their next duty station for them. If you report to Carson with 4ID orders, no matter what anyone in any other unit tells you, when you finish inprocessing, 4ID will come and pick you up.

Then I highly suggest you do exactly as the SFC said and show up there FIRST. You do not sign in, you go there before your report date and speak with their S-6 NCOIC and proceed from there. They can guide you from there.

The chances depend on how you impress this NCOIC. Bring your A game and shoot straight, don't BS. No one can tell you your chances because it boils down to you, what they think of you and the needs at the time.