Hi sparker, your carburetor does not seem to be the one normally found on a Suzuki M120X - they usually have an emulsifier, and yours does not. No doubt there are other differences too.
Let's see if Mark Electric, a notable Suzuki mower engine enthusiast, can place it. Meanwhile you might look at this thread:
https://www.outdoorking-forum.com.au/forum/ubbthreads.php?ubb=showflat&Number=49918&page=1
