The labor rate is about the going rate these days for skilled service. But the $500 inspection fee is crazy!!
I could see $50 to take a look at your rifle but $500??? They clearly Don't want to do any work on guns.
But $90 per hour is actually good. Try and take notice when you take your car in to the shop, it's normally $150 per hour.
Diagnostics runs around $250 which normally applies to the final repair cost if you have it repaired there. (This is so people don't just bring things in to get diagnosed and fix it themselves)