I can almost always tell right away just from a split second glance at the headstock shape. And in this business, it's everything. I'd be glad to do custom pickups, electronics, frets, strap locks, etc. etc. Believe it or not, I actually get asked to do this. Some people even offer me large sums of money.
Different styles require different set-ups.
The right set-up makes a huge difference. Since my shop is in my home, I don't invite the public. If you don't, I have a 48 hour trial period for basses shipped direct from me.