Huvius,
Fun reading indeed - you can searching all issues (check out this one on Mauser http://www.google.com/search?tbo=p&tbm=bks&q=Mauser&tbs=,bkt:m,bkms:1168684103302644747 ). The returns come in two flavors - tax receipts for weapons and registrations (which *generally* have the serial numbers).
If you've got a rifle that you suspect might have come 'out of Africa', it's worth the time poking around and potentially finding the name of one of the old owners.