As you can see from the image above (click it to enlarge) the bodies and arms are being sold separately so you can choose to arm your troops in whatever combination you want. Just remember to buy the correct amount of right and left arms for your troops... you wouldn't want to be left short!
Here is the LINK to the shop.
As you will have realised, I am very happy about this and have already placed an order so expect to see a few more urban troops in powered armour very soon.