36 humpback panel outside door handle question

[36humpback]

My panel came without locking door handles and I would like to put some on it.  Is there locking handles that will fit?  How easy (or hard) is it to change them over?  Does the inside mechanism need to be changed too? Any help will be appreciated. thanks.

[road dog]

My 37 pickup has one locking handle on the passanger side. I had to replace the key cylinder, easly done once you remove ir from the inside handle and shaft. So you would neeed ot find at least one outside door handle that matched the look of the existing handle, but you would not be able to lock the door from the inside.