There's a John Morton Wilkinson in Pedigree resource files on familysearch, DOB 11 Jun 1850. The nearest birth reg to match this one is for a John Wilkinson, Lincoln, Sep qtr 1850 Ref: 14 536.
I would always send for a birth cert to check names of both parents. It's too easy to assume. There's no extracted baptism record for a John Wilkinson on IGI.
Another option would be to post a look up request on the Lincolnshire board for a look up for a baptism in Branston Parish Registers for 1850/51.
Angela