This is an area where I think "close enough" would be "good enough". Even though ships may come from a specific line, each one is going to be a bit different, so if you're switches and buttons are slightly different from another version, that adds to authenticity in my opinon, instead of detracting from it.
Remember we do have Exeter's set. I can use their buttons to create my own molds, only I was hoping to not need to. I've never made a mold for anything before. Until a couple of weeks ago I had never casted anything before or even thought about doing it. But by this time next week I'll probably have slightly irregular molds filling my trash can, and in a couple of weeks some usable molds and maybe even new buttons.