Correct. The founders wanted to protect the state Militia from federal infringement in no uncertain terms. There are no limitations or restrictions in the second amendment and none are necessary.
However, if one interprets the second amendment as protecting an individual right outside of the Militia, well, that leads to the discovery of limitations and restrictions on arms and keeping and bearing that I don't see.
I agree with you. The second amendment should be formally amended if, for example, "arms" are to be limited to semi-auto rifles, shotguns and hanguns.