You know, when I look at the basic hull shape of this thing I'm reminded of some of the pre TOS designs done by Masao
on his Starfleet Museum
website. Take away the fins and the landing wheels and there's the basic shape for a 22nd century pre TOS ship variant in it. One of those "primitive" ships Spock could be referring to in "Balance Of Terror." That is if you ignore ENT...which I have from the beginning.
For those not familiar with the site.