Even if Chevy Duty were to loose the case and the court were to award GM some catastrophic (to CD) award, they wouldn't have to pay it right away untill all their appeals were heard.
I'm not sure how far back AC-DELCO parts go back, but it seems to me that GM really relies on some of these outfits to keep churning out and/or selling aftermarket parts.. especially those "officially licenced" GM aftermarket parts.
My gut tells me this lawsuit was probably inspired by Chevy Duty not selling mostly "GM Licenced" parts, compounded by the model ranges they cover overlapping the AC-DELCO parts in the late 70's and 80's vehicles.
I say that, just because there are plenty of other outfits that have some variation of the bowtie emblem in their logo or the word Chevy and they don't get sued.
Maybe those other outfits aren't that big.. or maybe they're bigger, but play ball and smart enough to know not to $hit where they eat.