Named Ascended Weapons
Yes. The stat change recipe works for any ascended item, no matter where it came from.
However, do note that the item you get in return will be a generic ascended item with the matching generic crafted skin (Antique with the appropriate color for weapons, and the crafted Light / Medium / Heavy appearance for armor). So you’ll need to use transmutation to get your skin back if you want the skin of whatever item you threw in.
Oh. I must have missed when they fixed that because before it wouldn’t let me. Looks like I can put those weapons to use finally.