Yeah, if you're in BDCP, all you need to do is go by your local base with a flight medicine department. This will be the only location you can get it done because of the equipment and personnel needed for the physical. Make sure you have your medical records from BDCP and your military orders for your OCS date, all of which should have been given to you when you signed up. Take this to the customer service desk in the facility...you may have to ask where this is...and tell them you need to get into the system for a flight physical for OCS. They will then take your information and give you an appointment date, sometime in the near future.
Then, just show up and have fun! Also, I forgot to mention before that your previous medical records from BDCP will more than likely be with your recruiter at your command office. You'll need to contact them in order to get these sent to the medical facility.
Hope this helps and let me know if you have anymore questions. I'm BDCP too and just finished my pre-OCS flight physical.