Yes, I see what you mean.
I've been lurking on the trike board for a couple of years, probably a thread about rake, but an actual user said no rake needed on the Rocket - grain of salt, who knows.
There are some early Rocket conversions up for sale, one or two a year, and from the photos looked to me like no rake, but many owners make that mistake and have to correct it later.
Rewaco gives very little information, like even wheel base.
If I find any solid information I'll check back.
Common sense says rake is a must, I agree on that.