Thanks! Actually what I found out is that the 66763-1 filter kit for Western, Fisher, Blizzard plows is the same as the Blizzard 48316 filter kit. This makes sense since Blizzard was a division of Fisher. I even found a local dealer who has this kit in stock!They are not filters persay just metal screens. Unless they are ripped or damaged, cleaning will be suitable.
You can look on ebay for nos tho, there has been some there, any dealer can still order them as well, could also try your local hydraulic shop for aftermarket alternatives.