Yes the copy will work OK so long as server1 and server2 are both not using the mdf and ldf files whilst they are copying over.

Note that mdf and ldf files are many times larger than a backup especially if backup compression is used. You would be advised to zip (ie compress) the files before copying them across the network.

It might be the case that server2 will already need to have previously had the same database online so that it already knows which ndf and ldf to use. Recovery might not happen when attaching databases (I could be wrong). Recovery will definitly work if SQL is started with the right files in the right place ie as it has previously known.

Try it.