S&W Rev's: New style button = lock or not?

[Mickstix]

Hey all.. I was browsing the web looking at S&W revolvers and I start noticing there are 2 different styles of cylinder release buttons.. I also notice that just about all the guns with the newer button also have a lock.. So Im wondering, do "all" the S&W revolvers that come with the newer style release button ALSO have internal locks on them? Reason I ask is I came across one particular gun that has the newer button, but from the angle of the pic I cant tell if it has a lock or not.. You can see it in the pic below.. (The insets show a new style button w/lock, and an older button model w/o a lock) Thanks for looking!! Also, when did Smith start putting locks in the revolvers anyway?? Thanks again for your time!

 

[Snubster]

There are revolvers with the new style release without the lock.

 

[Majic]

The new style release came out quite a few years ago. Sometime back in the 1990s I think.

 

[Riss]

My 93 or 94 vintage 640-1 had the old style latch.

 

[Shear_stress]

They changed to the new style thumbpiece in about 1997. Locks didn't come until 2001.

 

[Mickstix]

OK thanks for the info!!