connectors like that one are not so complicate to find. soldering your ribbon cable at that end either is piece of cake, remove the connector and solder and you're done in 20 minutes
you don't need to find that old one, just find one for the same number of tracks, the same pin count an for the same ribbon type (i mean the ribbon thickness). the pitch between the pins is the key issue here, maybe it's a 2.54 one
i bet the connector pins will align correctly, some extra plastic for connector alignment can be cut, if the new one has them
go with soldering if the other ribbon end has some connector, you will separate the boards with the other one if you have to