I have to admit, if it were up to me I'd have just ordered them as they came -- though I don't know what was involved in making the custom nipple tops. But I have noticed that neither flats nor nipples fit flush in everything I have. Even the flat tops leave a tiny gap in the endcap on the Lambo. Both fit fine in the LT, ProVari and Silver Bullet though.
I investigated the Flat-Tops and found, Drumroll...
the Original Flat-Top under the new flat-top!
..that and the Original white isolator ring.
So 2 Flat Nipples and 2 Rings.
The New Flat Top is spot welded to the Original,

It's spot welded there by a Z shaped jumper tab.
Now why they placed a raised 'Flat-Top' on top of a 'Flat-Top' is beyond me. [Say What?]
All they had to do was slice off the Original grey wrapper and slap on the new, more robust, black wrapper while using the Original isolator ring.
Disclaimer: I discourage anyone from attempting to un-wrap their batteries to make them shorter. And I'm not responsible for your mishaps and actions. The Wrapper holds the insulator in place for a reason. There is both the + & - power right under that insulator separated only by a hair line gasket. By removing, a short can occur, even welding the new Flat-Top to the + & - of the battery. If that happens it will be in an instant! (Done it before when I slipped up) it will get Too Hot Fast to break the weld, These are 10 Amp high drain batteries!! so it would be catastrophic, and very HOT! (42 Watt Zero Ω Attie anyone? lol)
It is never recommended to dissemble batteries or attempt to mod them.
Now I went out and picked up some 2:1 Shrink Ratio 3/4" Polyolefin Shrink Wrap tubing in 4 foot lengths. Cost about $5 a piece, should be able to re-wrap about 20 Batts. I will be carefully removing the black wrappers, Masking off the + & - with tape to prevent shorts and cutting off the Z tab holding the second Nipple. It's important not to get any metal filings in the valley and shorting across the Hair Line gasket, (Woo Sparks! Frak my eye!)
After my Battery Mod, [umm..?] after my Battery Restoration, the Original height will be restored and the Co-Op Batteries will fit most devices again, ..that can use the Flat-Tops, the new Smoktech Gripper, Lava-Tube..
I'll post Pics!