That's a very good question.
These rims have no markings whatsoever. Not even DOT weight rating codes. The only clue is the rear center caps have a sticker that has a stylized M with "MODERN" under it.
Searches for brand name Modern have proven fruitless. And I noticed the rims look like those sold under other brand names, like
AWC Allied Wheel Components. Notice the center cap design. It's identical and intended to allow a round sticker to be placed on it.
Further searching brought me to who I think the real manufacturer is:
Zhejiang Starco Huanmei Auto-Parts Co., Ltd. I think this company is supplying these rims to a lot of jobbers and tire chains. Their website says they make 1.5 millioin of these a year. And the wheel on that site looks like the same pattern.
The ones on the FJ40 have held up well. Chrome is intact. Welds look very professional.
On the other hand, it appears my pickup has the same brand, bought at Les Schwab, but with no sticker on the center cap, though it has the recessed flat for it. No markings on those rims either. Anyway, the chrome has flaked badly, to the point where I threw in the towel and used metalic silver Rustoleum spray paint on them, what my neighbor derisively called "Mexcian chrome" when he saw me doing it.
And these are probably the same brand as the white spokes on the jeep trailer, which also came unmarked and also came from Les Schwab.
As to the offset, etc., I'm not sure how to measure that with the tire on. I'll be happy to do so if someone can provide instructions.
Also, one caveat... I found a slight score line on the inside sidewall of my passenger side front tire. Turned out the 90 degree zerk fitting at full lock to the right was scoring it. I replaced it was as short a standard zerk as I could find and it just clears now. Pay attention to small details like this when installing tires. Have the front end jacked up and turn the wheel lock to lock and also try to visualize clearance lock to lock under articulation.