[DeadheadNM]

Larry thanks, sorry two last questions fellas: are the frame joints (arrow in pic) welded and is the middle rubber seal between the two sliding panes still present? If not welded I'd take it (but if not welded screws should also be seen along the underside of the bottom rail). Non-welded sliders can be disassembled and weatherstripping replaced.

It may not be OEM but may be a period correct add-on like that in my GMC. Haven't seen those vertical "grab bars" on OEM sliders but have them on a avintage aftermarket slider. If the seams aren't welded there should be screws holding the pieces together. From what I can tell, manufactures switched to welding. Is a slider listed on your SPID? That window embossing can fade and be quite subtle but is present on OEM sliders.