Plastic pivot bar?

I can't figure out if my window had metal pivot bars, plastic, or what. This sash had one metal and one plastic on n the same window!
Which way should i go?

i measured it the other the other day and I'm sure it's going to work thanks for all you help I thought I was in trouble with this but you guy's nailed it
thanks again

I have been in the business from 1977 working in a window factory for 27 years then on my own repairing window and screens and I can tell you that those nylon pivot bars are only made for that type of window because that window was made by cutting a 45 degree angle then assembled then those pivot are designed to keep the corners from spitting apart , if the customer would look at the other end he could see that it also had a simular L shape but with out the pin sticking out.