Nope. Self taught. But with a background of a machinist, and basically being a kid that loved to take things apart and put them back together, I grasp the know how. I've modified every single gun I own. Glocks are SUPER easy once you dig into knowing how they really work, and of course AR's are just big kid tinker toys. I think I've assembled near a dozen stripped lowers at this point, and can completely strip a Glock down to a pile of parts in about 45 seconds.
I have compiled lots of specialty tooling needed to work on guns, and I'm buying more all the time. I should have a sight pusher soon so I can start swapping sights.