and 连接两个谓语动词时,原则上说它们应在“数”方面保持一致,因为它们是“共用”一个主语.但你说的这个句子比较特殊,and后可视为一个省略句,即为 all of them are sold out … 之省略.
顺便说一句,and 连接两个动词时,前后不一致的“特殊”情况是多方面的,请看几个例子：
I can and will go.我能去而且也会去.(见《牛津英语用法指南》)
I am and have been in good health.我身体很好,并且一直很好.(见《英语基础词汇用法词典》)
Your steak is being grilled and will be ready in a minute.您的牛排正在烤着,马上就好.(见《朗文英语语法》)
I have always paid my bills and I always will.我一向是付账单的,今后也总是会付的.(见《牛津英语用法指南》)