#1
Broke a tuning peg on my PRS se zach myers the other day. I've been meaning to switch out the tuners to something that locks for a while. Does anyone know any locking tuners that can drop in with little to no drilling? The current ones seem to be PRS branded klusons, or what PRS calls their "vintage style" tuners. Thanks in advance.
#2
those would be vintage style tuners , 9.14mm is the type, i can tell by the plastic knobs and the grommets. If there was nuts and washers on the headstocks you could tell in 2 seconds.

perhaps gotoh locking vintage tuners
the locking mechanisim in these is internal though by the looks of it, this is common on certain types of grovers you see. Stewmac sells them so ask their customer support any questions you may have about them.
http://www.stewmac.com/Hardware_and_Parts/Tuning_Machines/Solid_Peghead_Guitar_Tuning_Machines/Gotoh_Locking_Vintage_Oval_Knob_6-In-Line_Tuners.html

however there's a lot of great tuners out there that aren't locking, locking just makes string changes easier so really anything 9mm from schaller, gotoh, sperzel, schaller or whatever else is ideal.

i'm a fan of grovers myself so this is the first place i'd look as vintage tuners that are locking i guess terrify the "vintage" crowd so there really isn't the market for them I suppose. But without the locking mechanism except for that anomaly that I suggested first it's kind of a pipe dream.
https://www.grotro.com/Grover/VINTAGE