Just add to what mulaz said:
dd copies exactly the contents of the drive, including the deleted files, due to the different means of storing the data on HDDs and SSDs, the wear-leveler on the SSD is going to abstract away the actual positions of the bits on the memory chips from their representation to the user.
While that does not affect the user at all, it should be noted that an arbitrary address on the filesystem does not correspond with the actual physical address on the chip.
Also the HDD might not have its partition aligned, which could be a problem for recognizing it on the SSD, which again does not mean that the data isn't there and cannot be read back using
Also (2), if your SSD is bigger than the HDD, you will have to manually expand the partitions afterwards to make use of the rest of the space.
Also (3), if your SSD is smaller than the HDD, not all of your data from the HDD will be written to it and when trying to access it, you will get read IO errors... but I guess you were aware of that and had it coming.