Yep. That’s right. On a 2D monitor if you have no headtracking and if your POV is set to the right spot and if you dont get jostled around due to turbulence. Then the HUD image you see is valid.
As far as 3rd party devs. There are some significant limitations around HUD collimation.
indiafoxtecho (aka. Dino Cattaneo) released many aircraft for FSX and P3D and they all had a collimated HUDs, this includes the original T-45. But his MSFS planes (T-45 and MB-339) so far do not feature collimation.
Milviz is running into the same issue. They mentioned in a reply to a youtube comment that once supersonic FM and proper HUD modeling are in the sim they’ll release their F-100 (I screenshotted it and put it in the F4U corsair thread, here: MilViz Corsair for MSFS to be released any day now - #24 by ShinobiShadow)
It’s apparently a significant challenge and will require some cooperation on Asobo’s part to make it feasible for addon devs.