Thanks RAD. You're not wrong about that feeling when building a lefty. I had to check and double check everything as my senses kept telling me "it's backwards", "you're doing it wrong" !!!
I managed to get through the build, paint etc all well until assembly where I became a bit too complacent. Flipped the guitar over, pre drilled the strap lock hole in the horn only to realize I'd drilled it in the lower rather than upper horn by habit. Felt like a complete idiot.
A bit of saw dust and color matching to fill the hole, sealed it with superglue, gave it a quick sand and buff/polish and it's nearly invisible until pointed out.
I explained to the customer and took money off the end price because of this. He laughed about it saying such n such (a big name respected builder) did the exact same thing!
The customer also payed me more than I wanted rather than the reduced price as he was so happy with the guitar, then tipped me a bottle of gentlemans jack! I'd love to build another guitar for this guy, just wish he wasn't a lefty so I could play the thing!