And the objects version is in the trainz-build value in the config.txt file. Less that 2 is pre-TRS2004, 2 to 2.4 is TRS2004, 2.5 is TRS2006 and 2.6 is TRS2006 with SP1.
If you can't find objects on the DLS and you don't get help here, look in the config.txt files of kuids that have missing objects and see if the author's email address or web site is listed and contact him directly.