All Spinal Tap "DOBLY" jokes aside, you are correct. SR-D is a playback specification. The "sounds" are not produced in Dolby.
In most countries, a Dolby Approved studio is required, and a Dolby representative/engineer brings the DMU in and creates the SR-D master file, which a lab then puts on the physical film. Dolby requires a license fee be paid to actually do all this, so I would contact your Dolby labs directly to find out exactly how much that is. If you're studio hasn't been approved by Dolby for Printmastering, then you should find a studio that is, and find out how much they would charge for their time as well for your quote. Plan on booking at least a day there (more if it's a really long promo) to find out how the stuff you prepped in your studio, plays back in a proper cinema environment, and make any adjustments to keep the clients happy. There's also some excellent information here on Dolby requirements. Also check the room calibration thread at the DUC for additional info. Finally Dolby.com has some excellent white papers and articles on all this, if you have a fair amount of time to search (I find it difficult to get to where I want to go on the site, but that could just be me...)