Is this a possible future piercing 5* antigua!?

When you do the mission Crossing the Chasm (starter mission, not sure if doable once you reach Haven) you will come across this NPC knight wielding a greyish looking Sentenza. At first, I thought it ought to have been a sentenza. But it wasn't purple, and it looked more similar to the 3* antigua's colors.
Maybe the developers notice how all the piercing guns we have are all slow and don't let you move and they are finally adding this as a piercing antigua in the future?

aw dang I missed it, perhaps that spiral spy thing would have that NPC?

Doubt it. He's a generic NPC with mix-and-match default NPC items. He wouldn't have a unique model.

Oh, yeah. That is just a 5* model with Blackhawk's skin.

There's been a suggestion for piercing antiguas already and it was generally disapproved of, as the line already has elemental and shadow types.

The idea of a 5* Antigua was not exactly 'disapproved of', and the reasons for wanting one had a lot of approval- gunners don't have any 4/5* fast Piercing weapons. IIRC, Callahan is the only T3 piercing gun in the entire game.

Except the unbelievably overpowered Blitz and the Toxic Needles? Those piercing guns?

Oh, yeah, forgot about those. I shouldn't post when I'm half asleep.
I won't deny those are overpowered, because they are, but the idea here is a mobile piercing gun. How overpowered the Blitz is is irrelevant, even if that, too, needs some changing.

Oh no, there's been plenty of threads for a piercing 5* Antigua, and there's a pretty large amount of support for it.
Check it out: http://forums.spiralknights.com/en/node/38341
The appeal of the Antigua is the mobility that the other lines don't provide. Blitz is great and all, but its normal attack is nigh useless.

The ironic thing is that players complained about it when we had it- one of the largest concerns behind the antigua lines was that they were "only good for one enemy" you don't want to fight devilites/wolvers with a gun... that was the logic behind half of the antigua changes on the part of the community.

Aye, as Fehzor says, I'm accounting for support rates before the antiguas got changed, and the consensus generally was to just remove the piercing and keep shadow/elemental. Since then, there has still been support against it. It would be the only weapon in the game that leads to all three special damage types, which I think would be out of the question (personally)..
Also, the Callahan does count as the mobile piercing gun, whether it's preferred or not. And honestly I'd say that Blitz more than compensates for the lack of movement; there's absolutely nothing in the game (excluding pierce-strong enemies) that Blitz can't easily manage, even with the stand-and-shoot mechanic. ctr/damage times aside, it's really not that hard to manage...even the normal attack suffices on numerous mobs.
Buuuut that's largely besides the point of this thread so I won't argue that one too much, I just say that because I (again, personally) feel that it'd be largely un-needed, on top of making the antigua line off-balanced.

The complaints were that Argent and Sentenza (and RSS, in fact) were split non-normal damage. This made them weaker than pure weapons against "vulnerable" targets, and weaker than pure weapons against "neutral" targets too. And the vulnerable targets didn't complement the vulnerable targets of other weapons, so it was hard to work these weapons into an optimized loadout.
But you are right that devilites and pre-nerf wolvers would dodge a lot --- hence the popularity of Callahan among gunners, in the old days.

Example one- "They are bad because of split damage"
http://forums.spiralknights.com/en/node/15755#comment-89484
Example two- "They are bad because piercing damage on them doesn't fit"
http://forums.spiralknights.com/en/node/44567
A lot of NPCs have unique-looking weapons or armor and stuff. Thatd doesnt mean we can get them.
Relatively speaking, a piercing antigua is easy to do, swap damage and make a texture. I think they would have released it by now.