Lol, funny.
Basically I'm just asking if I could make the same amount by plugging an external GPU into a laptop as I would by building a rig with that same GPU and the other components.
The short answer to your question is "yes". Usually bandwidth tends to be the bottleneck for gamers that want to use another GPU via an external connection. (Before thunderbolt & USB-C options were available, some people would mess around connecting desktop graphics cards to their laptops via mPCIe.) However, for mining purposes, bandwidth usually isn't a big concern.
However, most of the external GPU solutions are expensive, so I would hardly consider them cost-effective methods of mining.