Bill,
If the Advents were unique, I would agree with you. There were half a million of the OLA made in eight years. Then came the New Larger Advent with similar sales numbers. You can find these speakers in almost every thrift shop in this country.
They are a great platform for modding, similar to the Dynaco Stereo 70.
I cannot build and veneer a cabinet for the price I can get used Advents or other speakers of that era.
Enjoy your build.