Why not? Clearly, Starfleet was confident enough on the functionality of the "Great Experiment" that it didn't build a testbed ship - it built a fully armed and equipped starship! Why not build two for twice the price, then? Or perhaps four?
We later see the Repulse, NCC-2544, supposedly a sister ship from that same era. Other ships such as Constellations get higher registries than that - the Hathaway is NCC-2593, and was commissioned in 2285. And by the 2290s, Starfleet is already experimenting on variants of the basic design, as with the E-B (and with the subtle reworking of the NCC-2000).
Timo Saloniemi
We later see the Repulse, NCC-2544, supposedly a sister ship from that same era. Other ships such as Constellations get higher registries than that - the Hathaway is NCC-2593, and was commissioned in 2285. And by the 2290s, Starfleet is already experimenting on variants of the basic design, as with the E-B (and with the subtle reworking of the NCC-2000).
Timo Saloniemi
