Answer
AI-Script install packages are versioned as follows:
jais-m.nZx.x-signed.tgz
For example: jais-5.0R2.0-signed.tgz
m.n is two integers that represent the software release number; m denotes the major release number; n the minor.
Z is a capital letter that indicates the type of software release. In most cases, it is an R, to indicate that this is released software. If you are involved in testing prereleased software, this letter might be B (for beta-level software).
x.x is the software build number and spin number.
You can download the AI-Scripts package at http://www.juniper.net/support/products/serviceautomation/