Window Sash Part

Hello,
I am attempting to identify the plastic/vinyl weatherstripping part that is shown in these images. We are restoring a home built in 1880 and due to a federal registry issue, we can only repair windows with 'like parts' and cannot install something that looks totally different. Thus, I need to find something that looks 'close' to this part.

The part slips into the bottom back section of the top sash (double hung design, but top sash is inoperable). It sits where the top sash and bottom sash would meet when the window is fully closed and I think helps prevent weather from coming into through the opening. The piece is white where I'm pointing, is almost double-ridged with approximate measurements of 3/8 to 1/2 inch tall. The piece is cut to the full length of our window so we need long pieces if possible.

Can you help identify this part or point me in the direction of something similar? Any advice would be greatly appreciated. Thank you so much!

Thank you,
Ashley

Thanks for the reply. Yes...I am trying to identify the actual weather stripping that is held into the meeting rail. The piece is physically located on the upper sash, but does slightly brush the lower sash when the lower sash is opening. There is a groove in the rail that it slides into, but glue is placed inside to hold the stripping firm. I hope that makes sense! :)

You are correct, in that they did not have any vinyl stripping back then (lol). However, we are approved to use this type of stripping on our windows, so need to stick with this type as shown in the picture if possible. Do you have anything that will work or be close to this? Thanks!