Create a freestyle build with 2 steps:

1. Copy artifacts from another project (pick a random project and filename, set it to optional, Latest successful build)
2. Execute Shell (contents: "set" - should work on windows/unix)
   RESULT: Shows COPYARTIFACT_BUILD_NUMBER_(project name) set as described

Create a maven build with 2 pre-build steps:

1. Copy artifacts from another project (pick a random project and filename, set it to optional, Latest successful build)
2. Execute Shell (contents: "set" - should work on windows/unix)
   RESULT: DOES NOT SHOW COPYARTIFACT_BUILD_NUMBER_(project name) Set!

Hopefully this is an easy and quick fix...thanks!