Hi Chris, welcome to Outdoorking.
If you post the long series of numbers stamped on the cooling air cowl of that Briggs and Stratton engine, we should at least be able to tell you when the engine was made. In most cases the mower is made just a few months later.
Meanwhile Bruce may be able to tell us who made that mower and what the manufacturer's model number was(AFAIK Victa did not make ride-ons, they just rebadged other people's machines).