Hi Brian,
The problem is that you exporting a PCB file and not the Simulation models from Altium. You will need to create a .REF or a .QPL in Hyperlynx so you do not need to re assign it every time you load a .HYP file.
The .REF and .QPL can be created in Hyperlynx. Hyperlynx cannot load Altium simulation model files.
Hyperlynx can use IBIS, SPICE, S-parameter … files, which you assign when you load a .HYP file.
The .REF file uses designator to assign models. The .QPL file uses part numbers to assign models. Search help for automapping.