We don't anticipate that knowing how to do things in BGScript will be of any particular benefit to learning NWScript. An ability to code in almost any procedural programming language (including BGScript) is of use to understanding the logic flows in a language such as NWScript.

Having said that, in some cases, knowing BGScript may actually lead you down the wrong path. The AI system within Neverwinter Nights is subtly different than the system inside the Infinity Engine games (BG, BG2, et cetera), and internal designers who have done a lot of BGScript have been quite surprised that not all scripting languages work exactly the same way that BGScript does ... and it's the very small differences that cause the most difficulty.