I went to ainslie today to pick up my PMs and they gave me this with a couple of the newer ones, I asked if they had more and he said no.
That's curious - the bars I bought in 2007 were the "casted" type (yes, 1Kg too) - I wonder if they had both types available and I didn't realise it?
Possibly the bars bought in 2008 were buybacks. I've got one - they're nice, but pretty sure they had to be manually shaved to correct weight after being extruded (or cut from bar stock) - see if the edges look like they've been hit with a grinder. The current cast bars are literally cast from 1000 grams of measured shot placed into the mold, and heated, so no messing around with perfecting the weight of the bar afterwards.