Bingo. But integrated amps often DO have two caps in series, if they're equipped with pre-out and main-in jacks.
I have long harbored a prejudice against power amp input DC blocking caps, because I feel that a power amp should never be tasked with band limiting. This job is more properly delegated to the Control Amplifier, aka Preamp or Line Amp, which must never be guilty of emitting DC bias or any other signal pollution to downstream components.
On the other hand, some power amps need input DC blockers to prevent themselves sending DC bias upstream and possibly making the preamp volume control noisy or worse. Also, it has to be admitted that real-world power amp manufacturers will encounter customers with non-ideal signal sources and preamps. Without band limiting circuits, some of these customers will experience substandard performance and blame the wideband amplifier, resulting in lost sales. It's a bit too easy to criticize manufacturers who include band limiting circuits if you don't have a hungry family (or stockholders) to feed.