Looking at getting a new 20 or16 ga. O/U browning citori .....so far only the chambers are chromed, not the barrels.

How important is this.......

My 17 yo Weatherby skb orion I has chrome lined barrels....

Not important at all. Most of the best guns in the world do not have chrome lined barrels.

Thx......does the chrome thing have something to do with steel shot?

Chrome lining will reduce or prevent corrosion. The only downside is if one wants to modify the existing barrel. Forcing cones, etc. The lining is harder to grind.

No, however all new Browning offerings are steel shot compatible.