If memory serves, the ST5 engineering is the Jefferies tubes with a few consoles in it. The original sets were made for season 1 of TNG's "Too short a season" as underground tunnels there and were originally the Enterprise-D's maintenance corridors in "The Hunted" before the official Jefferies tubes sets were built.
http://tng.trekcore.com/hd/albums/3x11/the_hunted_hd_287.jpg
Definitely not the regular Stage 9 sets in ST5.
http://tng.trekcore.com/hd/albums/3x11/the_hunted_hd_287.jpg
Definitely not the regular Stage 9 sets in ST5.