I'm with con-f-use on this one, although you will need to tidy up the existing PCB.
You might need to suck some solder off the pads where clearances are tight and also snip component leads where they lay over.
The fiddly bit will be drilling, as you will not have a center guide.
Having an artwork program, I would redo/update the layout, however it is not at all a dense or complex PCB and his process or similar should work just fine.