Yes, it is the 'Always Free' tier (almost identical to the Free Tier of AWS):
The Google Cloud Platform Free Tier is your opportunity to learn and
use GCP for free. It has two parts: a 12-month, $300 credit free trial
and Always Free. The 12-month, $300 free trial allows you to use any
GCP product. Always Free allows you to try participating products for
free up to their non-expiring usage limits, making it easy for you to
test and develop with these products.
In essence, it is completely separate to the free trial offered ($300 for 12 months) and is designed for developers to explore and develop applications and services that use the services included in Free Tier, without being charged (also note that a SLA does not exist with Always Free).
Usage of the Always Free tier does not use any free trial credit you may have:
You are eligible for Always Free usage amounts during the free trial period. Always Free usage does not count against your free trial credits:
For example, only the portion of your Google App Engine usage above
the App Engine free daily usage limits is charged against your $300
credit. In addition, if your App Engine usage is below the free daily
usage limits, your app will continue to run even after the free trial
ends.