Help on identifying an ancient gold coin?

I don’t have any experience in ancient coins and a friend sent me these photos of what looks to be an ancient gold coin. Any help is appreciated.
Collector
75 Positive BST transactions buying and selling with 45 members and counting!
instagram.com/klnumismatics
1
Comments
It looks like a Tremissis of Justin II (note Victoria Augustorum). However, I am puzzled by the image on the reverse, which appears to be Constantinopolis facing out. Maybe someone has a better reference than my old Sear.
DPOTD
I think you are right. SB 58
DN IVSTINUS PP AVG
VICTORIA AVGVSTORVM
https://www.pcgs.com/SetRegistry/collectors-showcase/world-coins/one-coin-per-year-1600-2017/2422
Thanks really appreciate it. Any idea of value in its condition? I’ll let my friend know.
Collector
75 Positive BST transactions buying and selling with 45 members and counting!
instagram.com/klnumismatics
Maybe somewhere between $200 - $300, but I am no expert.
DPOTD