Here's what happened: after thinking way too much about how much that "bump" was irritating me, I noticed that the threads on the tube itself were just as chromed (and looked just as good) as the ones on the end cap. My reasoning was, if I took the threads off the cap, maybe I could glue the shortened cap on the tube and straigthen the grips?
So that's what I did; dremeled the threads off the cap and sanded the cut smooth, leaving only a little bit of material for the cap to hold onto the tube. Then I straightened the grips with more dipping in boiling water. After that all was left was to glue the shortened cap on; I pretty much filled it with E6000 and installed it on the tube. The remaining thread was just barely keeping it on, the E6000 did the rest.
So there you have it: a visually accurate Larbel MPP with straight grips. I just wish I would've thought about that solution earlier; installing the grips with the modded cap would've been MUCH easier (and straightforward; no boiling water! :unsure)
As I found out by cutting it, the Larbel endcap is chromed brass. I sanded the cut smooth and polished it to make the brass as light as possible. So yes, the edge is metal.