是的，这里的确实是省略了 were，属承前省略。一般说来，在并列句中，若前后两句均为系表结构，且时态相同，通常可省略后一结构中的动词be。又如：

The scenery was beautiful, and the acting (were) superb. 布景很漂亮，演出也很出色。

He is a millionaire and his father (is) without a cent. 他是百万富翁而他父亲却不名一文。

Our flat is on the first floor and theirs (is) on the third. 我们的公寓在一楼，他们的公寓在三楼。

His vocabulary was sound and his grammar (was) excellent. 他的词汇丰富，语法也很精通。

With so many companies competing for consumers' attention, price competition was intense and profit margins (were) thin or nonexistent.  由于有很多公司要争取获得消费者的关注，所以价格竞争很激烈，利润空间很小甚至没有。