Channel Balance, sash guide, top and shoe

I have to replace the channel balances for the steel windows in my Florida apt. The one that looks like it fits is the 31 " 1/2 inch wide 377 series on your site. It has a 3020Z stamp on it (which is the weight -20 lbs- I believe. The problem is that I can recognize the top 19-018 (my top piece is not in too bad a shape) however the shoe from my balance is broken and the flaring piece is cut off. The piece I have is "white" and yours seems to be yellowish. It seems like the measurement of the two sides is 15/16" like your picture. The building is from the 70's in Florida. My question is do you think it is a match? Does that top piece 19-018 always come with that bottom shoe 15-005 on this type of balance? Also do you recommend replacing the sash guides and take out clips also? It states on your web site that Pan American was the company manufacturing steel windows, would that be in Florida in the 60-70's also? Thanks, Remy Ayache.