Yup, I know the meaning of Drop-In to be "sans-fitting"... that's why I put it in quotes.
As for the final finishing, I would imagine it wouldn't be that hard for them to get everything to correct spec... otherwise, they're just putting out a POS. It's not like the barrel and locking areas of the GLOCK are all that complex.
Now, I could understand if they made certain parts oversized (as they said in the description for "non-critical" parts) to allow for individual fitting to guns that may have some wear here and there to get it "just right"... but that seems a little weird to me. If you have a worn GLOCK and want a tight barrel, get a custom barrel. I guess if those Storm Lake barrels
are oversized, it would allow for a much cheaper custom barrel as you'd only have to pay for the gunsmithing/fitting.
I'm certainly not trying to sway you away from them, as I have no experience good or bad with this company, but I do know that over on GlockTalk (yeah, yeah, I know... I only go there for ammo 'from a guy') that there's a gentleman that works for
Lone Wolf Distributors and they have a very good selection of
barrels to choose from, many with things like porting and/or muzzle threading for muzzle accessories such as flash or sound suppressors. It does look like their prices have risen quite a bit from when I last looked (about 6-8 months ago) and the bbls that went for around $80 are going for about $114. It's understandable with the rise in metals and gas/shipping, though.