Beadman is right once again - there are repro pemma raka beads floating around - I should know I have some here.
That first pic is of the repro pemma raka type - but there is one genuine old bead in there - try and spot it :)

The second pic - a scan - shows two antique and two repro - its isn't too hard to see which is which!!!

Problem is though - if you're not often in contact with this stuff, and you're not able to make a comparisson,then genuine ID can be difficult - and that repro stuff is pretty nice in its own right. Much better quality than some of the other Tibetan repro - like false antique turquoise!!!

So another clue to whether its real or old depends on a pair of good eyes. With them, if you look down the thread hole of the old stuff you may well see a ridge - that indicates the thread holes where drilled from seperate ends and meet around the middle. The thread holes of the repro are always "smooth bore" - drilled in one go.