Does it have 3 through holes in the topstrap? If so that's for the standard scope mount.
IIRC the -4 the first of the 629's to run case hardened hammers/triggers.
I know none of my -3's were factory drilled and tapped for scope usage.
Some older 8 3/8" models had dovetails on the bbl for a more fwd scope mount, used special rings (a couple guys I know back in the day sent theirs in for rebarreling).
If it was a 6" or shorter I'd not mount a scope. Nice trim rigs, nice to kinda keep them that way.
But a scope can be good for aging eyes...........IMHO they suck for moving deer in the woods though...if your -4 isn't factory drilled and tapped for the standard mount you can send it to them for such modification. Or some nearby 'smith probably has the dims and can do it for you.
629's are nice, esp if it's pre lawyer lock. Even then, the more silly prices tend to be for the -3 and older.
Good deer hunting rig..........set it up the way you like and fill the freezer!
If it is not a Classic model it may not have what they call the "endurance package". Not sure what version they started that on in regular models.
Shooting heavy bullets can break your trigger pivot (did on my 4" 629-1). The endurance package was radiusing shoulders of pins and such to reduce stress risers.
Seems to work.
I'd run hot 240's and lighter in a non endurance package model.