Yes. The AICS magazine will accept longer .223 cartridges than the AR magazine will accept. The AICS magazine foot print is for .308 length cartridges. The .223 version magazine incorporates filler to suit the shorter .223 round, but will still accept cartridges with heavier bullets seated out.
AR magazines are more available and less expensive than AICS pattern magazines. I say AICS pattern because magazines are made by other than AICS.
Don't know about the 7, but my standard 700 receiver would not accept AR magazines in the PT&G bottom metal without milling operation to the bottom of the receiver. Others have reported differently.
Looking at the PT&G bottom metal @US$129? Looking for a Cdn business that has already imported them? Can't help there, but PT&G has sold different bottom metals direct to me.