jas,
For that price you should snap it up. Look at it this way, if it were a lesser English maker hammer gun in 28ga would you say no at that price? Any time you can find a decent hammer in a smaller gauge grab it.
There is a German 24 gauge hammer gun on Gunbroker now:
http://www.gunbroker.com/Auction/ViewItem.asp?Item=77342957This seller also thinks he has several 44 gauge shotguns. Wasn't too thrilled to hear they were actually 44XL.
BP has the hulls and carries Fiocchi ammunition:
http://shop2.mailordercentral.com/bpicart/prodinfo.asp?number=0642400http://shop2.mailordercentral.com/bpicart/prodinfo.asp?number=36524PLCheck Gunbroker. Several sellers with brass and loaded ammunition.
Pete