Raimey,
the 2 telltales signs:
-The lock holding pin is in the middle of the sideplate, which is the wrong location for a sidelock which would have 2 pins anyway
- As somebody else said, there are 2 pins on the action bottom. Sidelocks only have one. This is not 100% as some craftsmen went through the effort of hiding the 2nd pin with a slide, but that's quite rare.
Additionally, the "sidelock" pin placement looks off to me.
Best regards,
WC-