Friend had 50 shares in RR in 70s. Is there a way to find those shares? He was working for RR (UK) and issued as part of employment.

So my GF's Uncle was talking about his “shares” he was issued working for Rolls Royce in the 70s. He was given paper work at the time which is long gone. He says this was before they split the company to air/car. Any way to figure out if he can get them shares?

Sorry if wrong sub to ask such a question please direct me to a more appropriate sub. Thank you.