I have nineteen G&Ls, mostly strat bodies (Legacys, S-500s, Comanches and Legacy Specials; one ASAT Deluxe). I've bought most of them used. A couple came to me with aftermarket pickups and I've put Texas Hot Antiquity sets in these two; but other than minor set-up issues, they were all good to go--no mods needed.
I've never done any mods to my MIK or MIJ Ibanez guitars. Or my cheapie DanElectro Innuendo 12-strings, or the Takamine 12-string acoustic dreads. My Fender Precision Lyte bass was perfect, though I bought it used. My first Music Man Sabre II was perfect.
Some of my Martin dreads got a strap button put in the neck. My Taylor 710CE got a bone nut and saddle and Tusq bridge pins.
Schaller Strap Locks are a must on any Gibson, and all of mine have them.
Gibsons usually require a bit of set-up work--like a bit of nut work or filing the tune-o-matic saddles to match the fingerboard's radius. I don't consider action work a mod.
That noted, the four Historic LPs I have are perfect, no mods needed or wanted. Ditto for the 335s I have. (I MIGHT re-do one with Ants, an RS Kit, and new knobs--maybe a LW tailpiece.)
The two Les Paul Supremes needed new pickups; I've upgraded one with Seths and an RS Kit, the other TBD. Lightweight aluminum tailpieces--another good move.
The two 1960 Classics got new pickups (Ants in one and Custom Shop Seths in the other), RS Kits, LW stop-bars, and metal jack-plates for durability.
The two 2007 Guitar Of The Week Classic Antiques got metal jack-plates only. My LP Elegant got a LW tailpiece.
So the Martins, Takamines, DanElectros, Music Man, G&L, Ibanez and Gibson Historics really get the kudos for being closest to perfect right out of the box.
I tend to not modify guitar if I don't have to, and all of the mods I've listed are reversible.
I've only ever done one NON-reversible mod, and that was to a second Music Man Sabre II I bought--I had a third pickup added to it; a Sabre bridge pickup, and it looks factory perfect. Mike Lull in Bellevue, Washington did the work; fantastic job. And it works beautifully, brilliant mod--I couldn't be happier with it.
Bill