In 1988, I stopped in at SAnc. in Geneseo, IL to buy some parts and asked if they had any lock bar sights. I was surprised when they brought out a container of almost 500 they had. I only had enough money for about a dozen pinions, knobs and lock bars. I got half way through them when we had to leave, but I had found four that had checkered caps and knobs. The real early ones. No WRA ones in the pile, though.
Part of the reason SAinc. used lock bars in the 80's and easrly 90's was the Post WWII pinions and knobs were hard to find and cost a lot more. The OTHER reason SAinc. used them was on the receivers that would not accept the adjustable Post WWII sights, they could usually fit Lock Bars to them.