Safety on older Mini convertable

[Kensterfly]

Hi.  New guy here.  I have had this mini for at least 20 years.  Haven't fired it since it was new until I took it out yesterday.
I've been reading about the 'safety feature' and  can't figure it out on my gun, so I'm wondering if this older model even has it.
If it helps:  Serial number 071XXX. 

I can see the slots/detents between each chamber and if I pull the hammer back a bit I can rotate the cylinder until that detent is in the firing position between two chambers, but the firing pin will not seat in the detent and the cylinder does not lock in, it  can easily be rotated into firing position.

I have always been able to pull the hammer back just a little bit until it clicks, maybe 1/4 of a fully cocked hammer. The firing pin no longer rests on the round.   But I don't think the newer safety feature works that way, even though my cylinder looks identical to the new ones shown on this website. 

Can someone advise me if I am doing something wrong or if this is just the old type of safety that I have?   If it is old style, does NAA replace it under their lifetime warranty?

My wife and I just took our Texas CHL classes.  For the time being, she does not want to carry a larger gun but it quite willing to  carry this Mini.  (Now I'll have to buy another one for myself!)   I  want it to be safe for her.
Please advise.

Ken

[boone123]

Hold the trigger back far enough to release the hammer so it can drop  (fit ) into the safty notch, then release the trigger.
Use your thumb to control the hammer. You have to hold the trigger back so it doesen't catch the safty notch..