Maybe, but I'd like to think the Romulans have better things to do with their time than waste resources capturing and refitting a scrap-heap Fed ship. There's also a lot of technological problems with crossbreeding two distinctly different types of ships. The Romulans probably don't even use the same measuring scale as Feds, or different power relays, alternate plasma injectors, different warp fields...the list goes on.
No sane engineer would dream of taking the front end of a Russian Akula class submarine and welding it onto the back end of an American Ohio class, for example. All that time, material, and manpower would be better spent building a totally new vessel.