Mmm, I'm not so sure. If you read the Bluetooth 4.0 spec [1], it's very obvious on page 1047 (numbered 801 in the pdf) the exact advertising format, with its block of bytes for sending data. Sending a UID would be exactly what you would do, as a first approximation. There are actually much more interesting schemes that can be used - say if you don't want your competitors to be able to derive any information of their own from your beacons.

[1] - https://www.bluetooth.org/docman/handlers/downloaddoc.ashx?d...