A couple further thoughts.?
The factory TX and RX markings are from the perspective of a mobile that transmits in the 459 range and receives in the 454 range.
Sweep it to see where it's currently tuned.? That's what you should see if it's unmolested.
Also, this duplexer may only have about 60 dB of isolation because the carphone receiver had a Motrac helical filter to add isolation.
Unlike a typical flat-pack duplexer that is designed for high isolation on a single frequency pair, the carphone operated on a range of frequencies.
Those extra adjustments could be for optimizing flatness across the band.
