Rear wheel cylinder piston stop question...

[Reddartowner]

I have a question about a bracket called the wheel cylinder piston stop on the rear drum backing plates. Apparently the rear on my '68 Dart has 2 different backing plates, as one has the wheel cylinder piston stop bracket on it and the other side doesn't. My service manual says "newer model" cars came with the piston stop welded to the backing plate to keep the wheel cylinders from over-extending and losing fluid. So my question is..... when did Dodge make this change and do I really need the piston stop on my other backing plate...?? These are 10 x 1 3/4 brakes.

Thanks,

Mark.