burst disc

Lately, a few Coltri Sub Cylinder valves, without any provision of Burst Disc on one side, is doing the rounds. How safe would it be to try these valves out? And what could have made Coltri Sub release a valve without the safety feature of a burst disc?

I have some old tanks that I just had hydro'ed. They pass and as I was about to take the to the LDS to be filled. I saw a recommendation that valves should be rebuilt and have their burst disc replaced after each hydro. The rebuild kit look fairly basic, a new seat an a few o-rings and washers...