I've been in looking for a Brit 20 gauge for a while now, and I like Greeners, but I certainly would not pay that for a gun in that configuration (short barrelled, short stocked).
I really don't think barrel composition comes into the equation any more, there are as many of us who buy & shoot pretty guns (damascus) as there are who buy & shoot fluid guns only.
On a side note, the 12 gage gun linked as a refereence/comparison, has in my opinion no original finish at all, that consistent colour on barrels and actions suggests hot/caustic blue to me.
On another side note, it is possible/likely that a customer/client of Patrick's has consigned the gun and dictated the price. There is after all no harm in asking.....
Claybuster, thier photos, although of great quality compared to most internet vendors all seem to suggest radical cast, I have asked about guns & requested extra photos & never has the stock dimension been what the photos suggest.
M