The name of the .pbo file really isn't important (but if I where you I would use the same name for beta and not beta, (To be sure people do overight the old file with the new one).
The names you use to define the class of the weapon will have to be the same in both versions, or the mission makers will have to replace the name of the addons being used.
In the place where you define the weapon class:
ex: class earlSR47
this part should be the same always, because it's exactely the name the mission will look for.
Also there is something you should think now, will you use one .pbo file for all weapons?
ex: earlSR47PACK ? Or one .pbo file for each?
I'll explain you why you have to think about this now when you tell me how it will be.
As you know you can update the .pbo file with new weapons everytime you want to, this won't interfeer with the missions.
If need my help making the cpp file email me and I'll help you
filpedro@hotmail.com