SCM load and 'nix permission

I'm using the SCM load command to load a workspace on a linux system. The execute bit for user is missing on some files but not others:

-rw-r--r-- 1 lwpbuild cclwp 1623 Oct 18 09:41 tools.nam
-rw-r--r-- 1 lwpbuild cclwp 1309 Oct 18 09:41 undo_pack200.cmd
-rwxr--r-- 1 lwpbuild cclwp 64792 Oct 18 09:41 uniq.exe
-rwxr--r-- 1 lwpbuild cclwp 145408 Oct 18 09:41 unzip.exe
-rwxr--r-- 1 lwpbuild cclwp 39184 Oct 18 09:41 uuidgen.exe
-rw-r--r-- 1 lwpbuild cclwp 1007682 Oct 18 09:41 zapdir.exe

What determines the permission of files in the sandbox area?