1) Given only the pokemon information, no there is no way to tell. Spreads are generally counted against an initial seed of 0. Any spread that is obtained ridiculously far out from the initial seed is considered fishy. You can use this to make a general determination: Emerald Stationary PID (RTC). As an example, you can use suloku/st giga's mew to see the RTC of 30+ days. The seeds overlap after ~828 days.
2) I am not too familiar with the naming of "Pass NL (Anti-Shiny)" but IIRC, XD antishiny pertains to specific scenarios such as Pikachu, Celebi, and starting poke? Either way, antishiny is a different generation than the standard XD game which IIRC, can be shiny but are based on what you are encountering. Someone else like @Kaphotics, or @Admiral_Fish might need to jump in here.