"maybe I should have not purchased from the F.O. "
That is where mine came from, and I have the solid -no black center- driver. Mine got here a couple of weeks ago, "fresh off the line" as described from Amie...
TjB

Now the question... does the back look like the amp plate from the 350 pictures, or like the amp plate from the 500?

no the back is still like the old 350 i think they just found a new design for the driver and like myself & bb said its just a business decision not to by 2 different parts for the same job.

That's what I figured. I just hoped that Axiom might be doing a stealth EP400 on us...

Well, they sort-of did that. Depends on what the EP400 is

I'd love to see a comparison of the EP350 v1 and v2, along with, say, a VTF-3 and a PB12 or whatever they're calling it these days. Throw in a 500, and there we go.

No, I don't have the money, house, or SAF to do that myself, thanks!

Which brings me right back to one of my earlier thoughts regarding why I was left shaking my head about the somewhat lukewarm reviews this sub has gotten on these pages compared to the rest of the options in it's price range.
I have NOTHING to compare it to except my old Polk PSW300 (which was pretty much just a boom boom box with no articulation). But I can tell you that I am as thrilled with my EP350 as I am with the rest of my setup. It was the one item that I sat on the fence about the longest - 350 or 500 - and I am glad that I got the 350. It is perfect for my listening needs & my space, and goes as low and loud as my Sweetheart lets it! ;-)
TjB

So, I keep checking back here, hoping that someone from Axiom will have chimed in to illuminate us.
Nothing yet...
Alan? Ian? Amie? Brent?
TjB

ditto

Well, I got an email from Brent with an answer to the mystery driver in some of the 350's, but I'll wait a day or so and see if they pipe up on their own...
If they don't. I'll ask him if it OK to post his answer, but I do not want to quote him without his permission.
TjB