Add iPhone shutter count and serial number to EXIF data

At present neither shutter count nor the iPhone serial number are embedded in iPhone picture metadata. Is there an app for that? Reason: Pictures come into a database from multiple sources. Using the date/time stamp already gives collisions due to camera burst mode, and multiple photographers. I would like to assign each incoming asset an asset number composed of model+serial number+shutter count. This generally works for mainstream cameras, but it doesn't work for iPhone. Is there an app that would add this in automatically?