Dolly Towing 3G Taco

Yes, it's a 2nd gen (sometimes called gen 2.5, since it's in the 2013-2015 cohort). I have the normal electronic 2WD/ 4HI / 4LO switch.

The 2LO mod, at least, the one I have, refers to a 3rd-party after-market electronic interface box / harness that allows you to trick the relatively dumb 4WD ECU into allowing you to engage the transfer case LO planetary gear in 2-wheel drive. This is very handy for using the otherwise-almost-unusably-tall reverse gear on dry/hard pavement, esp. when backing trailers up steep, winding asphalt driveways as I sometimes do.

Read all about it here:
https://www.tacomaworld.com/threads/2lo-modules.708941/

Since finding one second-hand via TW forums about a year ago, I have used it 8 or 10 times, it's a clutch-saver for sure. Build quality is OEM grade, IMO the unit is likely to last as long as the truck does.