Can you order the rack so it will fit the light bar below? It is half the price as the the other light bar?
https://www.desertrat.com/products/?id=9033
For 40" straight bars, intuitively, I would guess that it would.
Now, for 40" curve bars, it would be good if you go hunt down(do some research) the mounting requirements (and please report back) difference between the 40" Rigid E and your above light, and the KEY info to find out is the distance between the mounting holes, that dimension maybe reduced due to the curvature.
My brief 2min google'ing:
Rigid 40" E, mounting holes are 42-11/16" apart
E 40" - Combo | Rigid Industries
Desertrat 40" Curve, mounting holes are 43.3" apart
https://www.desertrat.com/products/more.asp?id=9033
The clearing of the vertical support will allow the bar to be mounted in between the top and bottom tubes.
If you have already decided on your light, you may want to put that "mounting hole" request down in your "comment" when you place your order.
Now, it would be BEST if you actually have one of those "knock offs" in your hands before making the request, as a lot of times, the engineering and documentation efforts that went into knock offs are not on the same as those "original, premium" brands. So, I may be skeptical about their published numbers (they will always come back and point you to an impossible to find fine-print saying "specifications are subject to change".....LOL)
BTW, [MENTION=107769]Desert Dawg[/MENTION] is using one of those Desertrat Curve 40":
http://www.toyota-4runner.org/5th-gen-t4rs/168993-desert-dawg-build-what-switch-8.html#post1732898