Season shield single hung window

Thanks for writing in. Take a look at our S390-30 Channel Balance. Go over all the dimensions and specifications to ensure it matches your old hardware. You will need to select a stamp option. This is usually indicated by a stamp code on your old balance's metal channel; but if there is none, or you are uncertain, weigh your window sash. You can then match that exact weight with one of the weight ranges listed alongside each stamp option on the product page. 

By plastic bushing pieces, do you mean the Top Sash Guides? Either way, if you could remove the pieces in question and show them to us from multiple angles, we may be able to narrow down what you need. Many thanks.