plastic guide ?

This is a very, very old part. I don't think this kind of window is made too much anymore so racking this part down will be difficult. However we will try our best, so please bear with us just a little longer as myself and my colleagues try to locate this guide for you.

We actually do still sell some pressure shoes, which I believe is what you need. This is the type of parts used on commercial push out windows like yours. However our selection is limited; like Tom said, they aren't all that popular anymore.  Look at the list I've made for you and see if you could adapt any of these to work on your older window.