You Found it Deejay! I looked for an hour. lols.
Unkie,Do you mean you think the serial number is way to low for this date? If so I agree totally.
The first ad you posted for Sept,shows clearly the plastic wheel rotomo( check the wheels carefully) and also the plastic metal throttle control,Both features of the Later Rotomo 2. And since many mower examples have also shown clearly that the plastic wheel Rotomo started around the 75,000 mark,this puts The Rotomo Production of "38952" much earlier on in 1956. Now since this is a sales receipt NOT a production date,then I would have to say that through transport,consignment and sale it could have been sitting around for months before it was sold. Hope This is what you meant by the serial?
Have a look at the Ad that follows the Sept one..Nov womens weekly. See how all The Images are showing the Tin wheels AFTER the Sept Plastic Wheel Ad? Odd isnt it. But the Add is very flashy and maybe it was already held by womens weekly and reused,as its only a month difference from the Original Victa AD . I think ive said before they sometimes recycled or used the same ad for longer than they should have after new models were released,as we saw with the 2a and the model 3...What are your thoughts Unkie?