Copying folders in Windows 7 without changing created/modified date?

Robocopy should be up to the task. The Default copy flags are DAT (data, attributes and timestamp) so that should work.

As noted in the comments, the OP used the specific flags of

robocopy /E /DCOPY:T

Another option is to zip the directory, copy the zip and unzip it.

Works well if you have not that many files.

Tested it with the build-in zip functionality in Windows 10.