Just a Skosh or so. What would you do????

With as "hot" as that car might be I would darn sure check the chassis alignment as a whole, AKA rear axle alignment. There are ways to do that at home. Personally I would accept closer to 0 camber for more caster. (Assume you run radials) I've been told even -1/2 degree is enough camber

If you try and set up to check axle alignment bear in mind that front and rear track is likely different widths, as well as wheel offset

On a side point, "Are you sure" the gauge is accurate?" I don't measure caster by a gauge, I measure camber, and figure caster from two readings, taken by turning the wheels in/ out. So far as camber, all that amounts to is in/ out tilt and you can at least check the gauge for zero on a plumb surface, and you can check THAT with a level. Rotate the level so the bubble is reversed, and any error should stay on the same end if the level is accurate, IE you put a level on a vertical column, and the bubble, say, "edges" to the post side. of the index mark on the bubble. If you turn the level around, and if it's accurate, the bubble should still be on the "post" side. If it goes outside, the level is "off."