Sure, there is:
The earth was without form, and void; and darkness was on the face of the deep. And the Spirit of God was hovering over the face of the waters. Then God said, “Let there be a firmament in the midst of the waters, and let it divide the waters from the waters.” Thus God made the firmament, and divided the waters which were under the firmament from the waters which were above the firmament; and it was so. And God called the firmament Heaven. So the evening and the morning were the second day. Then God said, “Let the waters under the heavens be gathered together into one place, and let the dry land appear”; and it was so. And God called the dry land Earth, and the gathering together of the waters He called Seas. And God saw that it was good.
Then God said, “Let there be lights in the firmament of the heavens to divide the day from the night; and let them be for signs and seasons, and for days and years; and let them be for lights in the firmament of the heavens to give light on the earth”; and it was so. Then God made two great lights: the greater light to rule the day, and the lesser light to rule the night. He made the stars also. God set them in the firmament of the heavens to give light on the earth, and to rule over the day and over the night, and to divide the light from the darkness. And God saw that it was good. Then God said, “Let the waters abound with an abundance of living creatures, and let birds fly above the earth across the face of the firmament of the heavens.”
Genesis 1:2, 6-10, 14-18, 20 NKJV
Bolded are references to what we say are two firmaments. The distinction is in those bolded phrases, but also among the details linked to each:
The "firmament called Heaven" has the following features:
1. Created within water. The water is "the deep" of verse 2.
2. Has water above it, called "seas," and water below.
3. Is called "Heaven." Singular, capitalized.
The "firmament of the heavens" has the following features:
1. Has heavenly bodies created within it.
2. Has birds flying across its face.
3. It's of the "heavens." Plural, lower-case.
From our point of view, there are many distinctions and those differences are plainly in the text.
The firmament called Heaven is the granite crust of the Earth, which was broken into pieces by the fountains of the great deep (see feature 1).
The firmament of the heavens is outer space.
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