you know after seeing that opensourcematters.org guys used SMF as their board, I told myself, ok, it should be an excellent choice as they knew what to choose themselves! So, I went to mamboforge.net and picked the first SMF bridge I saw, which was Mambo-SMF Integration version is 188.8.131.52 by mambohacks.com
but today that I'm in here I notice that you are offering a different birdge. So, what is the difference between your bridge and their bridge? Is what you're offering sort of official SMF bridge for mambo because you are in SMF site actually?
I may be wrong - but as I understand it... he mambohacks bridge is not supported here due to to the way it removes the lewismedia copyright. there is nothing stopping you from adding it back in though ;)
SMF as you have discovered on the OSM site - is not GPL, although it has 'similar' values... it is protected under the simple machines license.
I would suggest that you use the smf bridge discussed here as you will get much better support for current and future versions of SMF.