You will see 29-5 and -6 with Square butt grip frames and mostly with the standard non full lug 4, 6 and 8 3/8 barrel lengths.
I would recommend the 29-5 and 29-6 as well as the 629-3 and -4 as they are pre lock and have the full endurance package.
If you just want a looker/collector a 29-2 with pinned barrel and recessed cylinder.