I know that there have been a number of discussions over the years about the merits or otherwise of fitting a copper gasket to a K-Series engine, can’t remember anyone in end doing it. There are car some concerns what will happen long term with two different types of metal and acidic OAT coolant.
I would be rather dubious about its effectiveness and suitability for the Rover K series - it appears from the picture on the listing to be a flat plate which would tighten down flat against the head and block faces and prevent any coolant from coming between the two - the original K series SLS/elastomer gasket allows very slim coolant passageways between the head face and block face and the central stainless steel shim. Bothe the MLS designs also allow for coolant passeways between the gaket and the head and block. This is a significant aid to cooling, and something the flat copper gasket is unlikely to give.
Bearing in mind the particular HGF issues associated with the K series, and the amount of work done by the engineers to rework the original gasket design, and then design a completely new gasket, if a copper gasket was as good as the claims in that eBay listing, why didn't they go that route? Says all that needs to be said imo.
Besides which, the SAIC 6-layer MLS seems to be very effective (I have mentioned before that my ZR had one fitted in 2013 and has since covered about 65 thousand miles and has needed no coolant topping up or had any other issues). A number of people are using them in track/race cars without any issues, and the engines in the China built cars that were factory fitted with the SAIC MLS do not seem to experience any untoward HGF, so I fail to see the need for experimenting with another largely untested design/type.
Just my two-pen'orth, but I wouldn't even consider the copper one in passing!