He would have been born about 1850, give or take a few years, so its possible that its a match.
The fact it is a writting desk is perhaps significant as his family wrote alot of letters, many of which survive. There is a publication of letters from the family which was published in Canada and another version in the UK. Both quite rare though I know someone with a copy in the UK. It may have reference to this somewhere, though the letters are perhaps a little earlier so maybe not.
Its likely this Jack, or perhaps a son, because there arent that many Jack Langtons at all, and certainly not many in Candada around that time.
I will see what i can find out and get back to you. Do you have a photo of it which you can send?