Replacement parts for Empire Pacific Alum Wnd 1992

Hi, thanks to your great site I have found what appear to be the parts necessary to repair the aging aluminum windows in my house. It was built around 1992 and has 'Empire Pacific' double paned aluminum windows. So far I have identified the balancer required as S351-21
Also what appears to be the correct seal: 58-045

However there is one more failure-prone part that I need, it's the sill 'bearings' or guide slides that are small u-shaped extruded clips that clip in little slots on the side of the windows to prevent metal-metal contact when opening and closing, and push the window toward the seals a bit. I've attached photos for you to see. Is a bag of these available from you?

Secondly, I can't see an easy way to slide out the old seals. Are cuts to the ends of the channel required?

Thank you
Andrew

Thank you for your response. Sure, here are some more photos. Note: None of the black top guides need to be replaced, just the J clip guides.

Also, to the other question, I plan on ordering balancers and seals from you, when installing the seals is it common to have to cut a slot in the seal channel to facilitate removal and insertion?

Did you ever figure out a part number for the j-clip guide?