best answer yes and no,
there are many completed electronics packages, most will have a generic firmware loaded.
The firmware loaded will not know the size of your print bed and the dimensions of your build envelope
It wont know where you have situated endstops and how they indicate they have been triggered
They wont know what sort of thermisters are in your heated bed or extruder, so they wiont be accurate in fixing a temperature.
So you need to go in and edit a firmware and let the electronics know all these things and more that i probably havent thought of, then you need to test tweak and reupload the firmaware till the printer moves accurately, and heats correctly.
I use the reprapdiscount ramps board (available from ebay) with marlin firmware and its pretty plug and play as such with the above changes made.
There are many such completed electronics kits out there, you can certainly connect it directly to your printer, but you will need to describe your mechatronic platform in great detail to the electronics so they know what to do when asked to home, move and extrude.
GaZ