My thought is that April's Enterprise in this universe was the ringship version.
Can't be. The ringship was seen in a painting on the wall of a bar in ENT: "First Flight," which means it predated NX-01.
True. I was basing my supposition on the information I found at Memory Beta, where one of the entries is based on Spaceflight Chronology
where the/a ringship Enterprise
is noted as in operation in the very late 22nd century and early 23rd century.