Tubes sound like a broken lightbulb

Depends upon how hard you shook them to elicit the sound you hear.  Don't forget those octal triodes have a large glass envelope with substantial metal and mica structures inside.  I do believe that if you shake such tubes GENTLY, you might hear that sound.  And I also believe that if you shake them vigorously, there is a good chance you could cause the damage that would lead to that sound of a broken light bulb.  So, if you can honestly say you didn't shake them vigorously, why not give the tubes a chance to see if they work OK?  You might be fine.

I agree with @lewm , give them a try. It could be part of the structure you hear, but it would not be a very loud sound.
If there is a rattling sound, it could be a small piece of the plastic base is loose inside. I’ve had a couple of these.

In any event, contact the seller and ask what he thinks it is.

Some heaters employ a spiral filament, which shakes exactly like an incandescent lamp.  Should be fine.  What really matters are the microphonics generated when in circuit.  Tap the glass with a pencil lightly.