I would be more concerned with the inside of the tubes, you know that calcification that really plugs old radiators up. A chem clean is always recommended on old rads with an unknown history. I've seen a lot of crud come out of old radiators when you flush them.

Of course most Behrs crack at either the hose neck or the small barb where the overflow tank attaches, if they make it to the point they are in need of rodding you just replace them

__________________
'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!