Here are a couple of photos of an original unrestored piece - it is part of a war memorial near where I live. It has been in the park since the 1920's.
The climate has been kind to this piece.
I believe the photos show the wood reinforcing originally attached under the base - the bolt holes look like they line up with the photos on the site above.
I'vr seen a fair number of lMWs in Southern Queensland - never seen one with any sign of wooden inserts under the base plate. The workmanship of the wooden inserts looks inconsistent with Rheinmetall or Krupp - suggest this might be a local modification applied to this mortar.
This is also the only one I have every seen like this. I have photographed many throughout both Victoria and NSW.
Most are either mounted directly onto concrete plinths or are badly weathered.
I was impressed with the work given close fitting joints, countersunk washers, crown nuts leading me to think it wasn't done locally but an original installation.
The mortar had been out in the weather for 85 odd years so the wood work has deteriorated.
I would be interested to know if it is original or not - perhaps photos from original examples stored in Museums - Australian War Memorial perhaps or one of the European Museums.