Pretty sure the JTV comes without strap locks and just standard strap buttons, as to suggestions It really boils down to preference. Dunlop, Schaller, Hennessey etc. I prefer Dunlop as they have a larger button that can be used as a strap button in the event you have a different strap or forget the one with the locks on it. All have their merits and just like anything else that has a mechanical connection that system does require the occasional drop of machine oil to keep it from squeaking.
I have been using them for as long as I can remember and have not had an issue. I have also tried the Schaller version and they work well also but I liked the larger button of the Dunlop better so I have stuck with them.