A 7805 is no different than a capacitor or a resistor, it's an off the shelf part, from a reputable manufacturer, comes with datasheets, tests, it's an established components (years if not decades old, classic design) and so on. It has three pins: input, ground, output ... it's a basic dc-dc converter. Can't be more simple than that.
Just like you buy the tl317 pcb from a store, you buy the 7805 from a store... what difference does it make that you plug the tl317 pcb on your design, or you plug a 7805 on your pcb... it's simple pins.
And like I said, this 7805 can provide up to 1A needing only about 1-1.5v above the 5v to be stable - so 6.5-20v would be no problem.
His rule makes sense only if you'd make a switching converter or something you plug in the mains - customs designs would have to be EMI certified and all that, which costs money. But this is not a part or design you make from zero, you're not making it out of transistors, diodes, resistors etc so it doesn't have to be tested or certified.
Anyway, if you insist on getting something manufactured buy a company, buy one of these then, it's off the shelf, commercially made, with all the guarantees and stuff your boss wants:
http://www.digikey.com/product-detail/en/RI-1205S/945-1191-ND/2256371Unlike linear regulators which must have a bit over the output voltage to work right ( in your case about 2-2.5v), these are switching regulators and in addition the one above it's isolated. It takes anything between 10.8 and 13v and outputs 5v without warming up.
The downsides is that there will be a slight bigger ripple on the output (being switching kind) and the minimum input voltage is higher at 10.8-11v.