Yup. It's basically discouraged everyone who took a shot at it.
Basically the criteria for a possible skin choice is;
1) Silver/Metallic only
2) No kill markings or Nose arts
3) Preferably no invasion stripes
..
That'd leave the only possible P-38L to be a generic '44 Silve/Metal P-38L with no individual markings at all, and possibly tail markings.... except I haven't seen any J or L looking like that so far.