Waldron do a set of instruments (which require a special, expensive, set of punches,) and a cockpit placard set; the problem is Roll Models, the present owners of the Waldron items, have a set minimum postage charge, which, for a single (lightweight) item, is prohibitively high. If you make up a sizeable order, it makes things more reasonable (or less expensive, depending on your point of view.)
Grey Matter Figures
www.greymatterfigures.com have a few resin items, like seat and control column.
Eduard do pre-painted 1/24 seatbelts, and 23005, being labelled "early version," should be a Sutton, though, speaking personally, I prefer to use buff-coloured carpet tape.
Edgar