Would we recognize them if we did?

We would definitely recognize them as something out-of-time and not the artifacts we already discovered. Whatever form and purpose they could have.

possible technology could evolve in completely different ways so as to be totally unrecognizable to what we have now.

That's not how technology reveal itself. Even if it is highly advanced technology, beyond current knowledge. In any case there should be "magic wand" that could cut rocks, f.e. and it will be different from anything we already found. This is not a rare situation, when archeologists who found some tool spend years to figure out its purpose. And I never heard that such artifacts was hid, on the contrary, information about such things spread between archeologists in the hope that many people discover thing purpose much faster than single researcher.

Taking in account that it is "unrecognizeable", it obviously will not be hedden, because as it is "unrecognizeable", nobody will suppose that it is some powerful advanced technology.

If that is the case, we should have today tons of technological artifacts of an unknown purpose. Any more or less advanced civilisation have to use tons of technologies. And there should be not only "magic wand to cut the rocks", but also things to move the rocks, to measure the rocks, to polish rocks, and that is only beginning - there should be much more things to make all that tools for rocks.

F.e. to make a simple tool like drill bit possible, you need a large amount of complex tools. You need whole industries for that.

There is no any traces of complex industries that will make possible mass production of that "unrecognizeable" tools to process rocks.

Also, hardly civilisation that have a super advanced technology to process rocks will use only rocks to build huge buildings. It has to have much more advanced materials for building than rocks.

Would we recognize them if we did?

We would definitely recognize them as something out-of-time and not the artifacts we already discovered. Whatever form and purpose they could have.

possible technology could evolve in completely different ways so as to be totally unrecognizable to what we have now.

That's not how technology reveal itself. Even if it is highly advanced technology, beyond current knowledge. In any case there should be "magic wand" that could cut rocks, f.e. and it will be different from anything we already found. There is not a rare situation, when archeologists find some tool and spend years to figure ot its purpose.

Taking in account that it is "unrecognizeable", it obviously will not be hedden, because as it is "unrecognizeable", nobody will suppose that it is some powerful advanced technology.

If that is the case, we should have today tons of technological artifacts of an unknown purpose. Any more or less advanced civilisation have to use tons of technologies. And there should be not only "magic wand to cut the rocks", but also things to move the rocks, to measure the rocks, to polish rocks, and that is only beginning - there should be much more things to make all that tools for rocks.

F.e. to make a simple tool like drill bit possible, you need a large amount of complex tools. You need whole industries for that.

There is no any traces of complex industries that will make possible mass production of that "unrecognizeable" tools to process rocks.

Also, hardly civilisation that have a super advanced technology to process rocks will use only rocks to build huge buildings. It has to have much more advanced materials for building than rocks.