Sorry to sound like a stuck record, but the TOS shuttle has warp nacelles. They look EXACTLY THE SAME as the ones on the Enterprise.
Who honestly believes that starfleet would build impulse engines into the exact shape of a warp nacelle? With every detail?
How is there any dispute over this?
Up next: How the transporter on the Enterprise-D was actually a food replicator made in the shape of a transporter.