Range,
There are a bunch of reasons why the speed could be slower for BOTH bows.......I've gotten speeds with the same set-up as much as 12fps different from 3 different chronos I shoot thru and they are ALL THE SAME MODEL! Every shop swears THEIR chrono is correct? Even HOW you shoot thru a chrono can affect speed by way more than you would think. Speed is always a tough entity to pin down.

My guess is that yeah it's probably one of the low end speeds, plus BowTech rates their speeds with only a tied in nock set. The brass one will drop the speed by 2 maybe 3fps vs what BowTech uses,so you could be looking at a high 290's (298ish) bare bow to begin with.
I know mine came from the factory at 300fps with the hush kit and brass nock, so if I took off everything it would probably only be a 304-305 rated model. Middle of the road.
I've heard the hush kit is only eating up 2fps on most models.

Throw in any variance in Chronos and the speed is easily accounted for, I think BowTech has always stated that shooters should watch for as much as a 2% variance in stated speeds in either direction just because of how different chronos can be.

When I get mine through a chrono I'll be sure to list the speeds I got with everything precisely weighed and measured.
I have actually measured my AMO draw length and it is quite good! My bow comes in even better than the "Test" bow at a HAIR under 30 1/4" I can't quite call it 30 1/4". That's VERY good if you know anything about stated draw lengths VS. actual AMO.

I would love to go into the draw lengths I had on some other manufacturers bows I've owned but its almost Christmas.