Does giving glory to God after the earthquake mean those Jews are saved?
No. Giving glory to the God of heaven after the earthquake does not by itself mean those Jews were saved. They recognized that God was working in their midst, but the text distinguishes that recognition from salvation; merely ascribing glory to God is not a salvation experience.
Les cautions that the remnant's response after the earthquake was not automatically a salvation experience. At the tribulation midpoint, a great earthquake strikes the area of Jerusalem; a tenth part of the city falls, seven thousand are slain, and the remnant are affrighted and give glory to the God of heaven. Even though these Jews recognize that the God of heaven is working in their midst, Les explains that merely ascribing glory to God is not salvation. Many people ascribe glory to God constantly, but that alone does not equal salvation. So the passage presents recognition of God's working, not a salvation experience.
And the same hour was there a great earthquake, and the tenth part of the city fell, and in the earthquake were slain of men seven thousand: and the remnant were affrighted, and gave glory to the God of heaven.