Which specific sailing are you looking at @57eric?
Is your travel agent quoting you Cunard's "Value Fare" or what Cunard is calling "Our Lowest Fare"? Those fares are guarantee only. That may also be the case for other special promotional fares.
If your travel agent is quoting you the higher "Launch Benefits Fare" or the "Cunard Fare" you should be able to get a specific cabin assignment. A few popular cabin categories might be guarantee only at this point on those higher fares, but it would be unusual for all cabin categories to be guarantee only.