A tough one Andy. Would very realistic replicas be acceptable ?
Genuine weapons, obviously 'De-act' of this type are relatively hard to come by, and command stupid prices due to their nature, unlike, for example WW2 type, but post-war manufactured small arms (infantry), such as the Bren gun, and even those,commonly ex- reserve stock Australian issue, are fairly expensive these days.
I can ask some of my contacts from a few years ago, but, as they were mainly involved with 'non- aviation' weapons, it's doubtful if they can help.
However, the guys at The Shuttleworth Collection, for example, have manufactured very accurate Brownings for the rebuild of their Spitfire MkV and, although basic replicas could be made by virtually any engineering shop, the above have their drawings, have made some examples, and could, I would think, produce more if needed, more accurately, and relatively easier, than 'Joe Bloggs' around the corner.
Admittedly, it would be costly if you had them, or a similar outfit, make ten for you, especially adding the cost of shipping, and the difficult Customs and security clearance costs, but I would think it would be a darned sight less costly than the real thing.
BTW, The Shuttleworth Collection is at Old Warden, about a half hour drive from where we'll all be staying for the DX weekend.
It might be a long-shot, but, they might be able to help, or advise, for a 'fellow' preservation organisation / museum.
Here's a pic of one of the Brownings they've produced, which, had I not read the notes alongside, I would have taken as the real item.