It seems to me that...
You have a couple of choices.
Since on my cars - the hood hinge attaches to the inner fender, using 10mm I do believe.
I'm not sure where it attaches on your Regal. Probably back near the tail light housing - but - For the purposes of this blog, let's assume it is at the same point.
Those holes are large enough to allow for a decent sized adjustment.
How do I know?
When I replaced them with stainless bolts, my hood raised up by the same amount of smidge you are talking about.
Try that first- with the shock absorber disconnected so it is not exerting tension on the hood.
If still no joy:
Then....Loosen all the outer fender attachment points, loosen the inner fender points; and raise the rear of the inner fender up just a smidge. Remember, you have that bog ole bolt that attaches the inner fender to the firewall - underneath down by the frame- it bolts vertically and I think the factory put a variety of shims in there for that adjustment.
Then - back near the A-pillar; jostle the outer fender down just smidge - not super easy since the top is more or less controlled by those 6 or so 6mm outer fender to inner fender body bolts - that run along the top of the inner and outer fender
But it is those two big bolts on the A-pillar that do the man's work of holding the outer fender in place at the A-pillar.
Or consider elongating the hinge holes just enough to allow for a little more up/down adjustment. But that will take some doing since the hinge is some pretty thick material. and I don't think that iss necessary - since there are plenty of adjustment points to not have to hog out the holes of the hinge.
Maybe a combination of all of the above.
I suppose you could shim between the hood itself and the hood hinge - but that is just so...lazy.
Or - you could just call it - what is that term you used - oh yeah - "character"
Who's the shim now?
I think any one who has ever put a body back together gains a new found respect for those "ignorant, beer drinking, union workers" who assemble these things and get the gaps to a nickel's width.