Electric and Gas at the same time?

[FairleeMansion]

I have a Grand Colonial built in 1897. Throughout my renovations, I notice that wherever there is a knob and tube wiring light fixture, there is also a gas line from the original gas lighting. It appears that the knob and tube wiring was installed the same time as the gas piping in the walls throughout the house.
I am basing this on the plaster walls not showing any signs of being patched as if someone installed the electrical wiring at a later time. My question is, Is this something that would have been done back then at the time of house construction? The builders maybe knew that electricity service was coming to the area soon and therefore installed wiring along with the gas pipes?? Any ideas? Thanks

[lgraven]

I have the same thing in my house in South Carolina, built c. 1890.