I'm reasonably certain that the numerical ID numbers refer to the number of seconds since 0:00 January 1st 1970, that being the start of the Unix Python epoch.

import time
print "Epoch started at:"
print time.gmtime(0)
print "Number of seconds from the start of the epoch:"
print time.time()

Running that this morning gave me a seconds from epoch start of 1330436377 which is comparable to the numbers found in Anastasia.

Poser is generating the ID number and the weightmap. Weightmap editing tools are found in the Joint Editor of Poser Pro 2012.

Similarly I am of the opinion that the weightmap format is vertex ID number followed by the proportion that the vertex will move. Zero does not move, 1.000 fully moves.

Which just goes to prove that some of us should get out more :)