Good afternoon everyone

I bought a used 12 ga. O/U Miroku this morning. Nice shotgun.
Almost new. 28" barrels 2 3/4" chambers. Extractors, not ejectors(that's fine with me; getting too old and fat to be bending over & picking up empty hulls) non-selctive trigger.
My question concerns the choke marking: top barrel is "+-", there is no choke marking for the bottom barrel that I have found.
Can anyone tell me what choke I have?

Thanks